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Procédure : nettoyer les métadonnées pour la synchronisation collaborative (non-SQL Server)

Notes

Les rubriques de cette section de la documentation, Synchronisation d'autre bases de données compatibles ADO.NET, montrent comment les bases de données autres que SQL Server peuvent être synchronisées à l'aide de Sync Framework. Dans cette version, SQL Server est utilisé dans les exemples de code, mais le code peut être utilisé pour d'autres bases de données compatibles ADO.NET, en apportant certaines modifications aux objets SQL Server (tels que SqlConnection) et aux requêtes SQL présentées. Pour plus d'informations sur la synchronisation SQL Server, consultez Procédure : configurer et exécuter la synchronisation de bases de données (SQL Server).

Cette rubrique explique comment nettoyer les métadonnées du serveur pour la synchronisation de bases de données d'égal à égal dans Sync Framework. Le code de cette rubrique décrit les classes Sync Framework suivantes :

Pour plus d'informations sur le mode d'exécution d'un exemple de code, consultez « Exemples d'application dans les rubriques de procédures » dans Synchronisation d'autre bases de données compatibles ADO.NET.

Présentation du nettoyage des métadonnées

Le nettoyage implique la suppression des métadonnées des lignes qui ont été supprimées d'une table de base. La synchronisation d'égal à égal utilise deux types de métadonnées :

  • Métadonnées de niveau table qui effectuent le suivi des insertions, mises à jour et suppressions pour chaque table qui est synchronisée.

    Il existe une ligne de métadonnées pour chaque ligne dans la table de base. Si une ligne est supprimée de la table de base et que tous les nœuds de toutes les étendues l'ont reçue, la ligne de métadonnées peut être supprimée sans risque.

  • Métadonnées de niveau base de données qui effectuent le suivi des modifications reçues par chaque nœud d'autres nœuds.

    En règle générale, ces métadonnées sont stockées dans une table d'étendue pour chaque base de données de nœud. Les lignes de la table d'étendue ne doivent jamais être supprimées, à moins que l'étendue ne soit elle aussi supprimée.

Pour plus d'informations sur les métadonnées, consultez « Créer des tables de suivi pour les métadonnées par table » dans Procédure : approvisionner une base de données serveur pour la synchronisation collaborative (non-SQL Server).

Le nettoyage de métadonnées est géré par l'application. Pour les bases de données SQL Server Compact, utilisez l'objet SqlCeSyncStoreMetadataCleanup :

  • La méthode PerformCleanup est celle que vous appelez à partir de votre application.

  • La propriété RetentionInDays est celle qui spécifie l'ancienneté, en jours, que les métadonnées de suivi des modifications doivent atteindre avant d'être supprimées lorsque la méthode PerformCleanup est appelée.

Pour les autres bases de données, il existe trois composants de nettoyage des métadonnées :

Contrairement à d'autres commandes sur l'objet DbSyncAdapter, les commandes de nettoyage ne sont pas appelées automatiquement dans le cadre de chaque session de synchronisation. Elles sont appelées uniquement lorsqu'une application appelle la méthode CleanupMetadata. La commande que vous spécifiez pour la propriété SelectMetadataForCleanupCommand peut utiliser n'importe quelle logique qui est appropriée à votre application, mais elle utilise en général une stratégie de nettoyage par rétention : les métadonnées qui sont plus anciennes qu'une durée donnée sont supprimées. Si un nœud essaie de synchroniser des modifications dont les métadonnées ont déjà été nettoyées, une exception de type DbOutdatedSyncException est levée. L'événement SyncPeerOutdated est déclenché, ce qui fournit l'accès à un objet DbOutdatedEventArgs. Il existe deux options pour gérer cet événement :

  • Affecter à la propriété Action la valeur PartialSync. Cette opération permet de synchroniser les données pour lesquelles des métadonnées sont présentes, mais certaines suppressions sont omises.

  • Affecter à la propriété Action la valeur AbortSync (qui est la valeur par défaut). Cette opération met fin à la session de synchronisation. Le client doit être réinitialisé dans la session de synchronisation suivante afin que ses données soient correctes.

Éléments clés de l'API

L'exemple de code suivant spécifie une commande pour la propriété SelectMetadataForCleanupCommand. La procédure stockée qui est appelée, sp_Customer_SelectMetadata, prend comme paramètre une durée en heures. Il s'agit de la période de rétention des métadonnées. Les métadonnées qui sont plus anciennes que cette période de temps sont nettoyées. Si vous passez une valeur -1 à la procédure, toutes les métadonnées sont nettoyées, indépendamment de leur ancienneté.

Notes

Cet exemple illustre une approche en matière de nettoyage des métadonnées. Il n'est pas obligatoire que la requête ou procédure utilise une valeur de rétention comme paramètre ou la valeur -1 pour indiquer que toutes les métadonnées doivent être nettoyées.

SqlCommand selMetadataCustomerCmd = new SqlCommand();
selMetadataCustomerCmd.CommandType = CommandType.StoredProcedure;
selMetadataCustomerCmd.CommandText = "Sync.sp_Customer_SelectMetadata";
selMetadataCustomerCmd.Parameters.Add("@metadata_aging_in_days", SqlDbType.Int).Value = metadataAgingInDays;
selMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncScopeLocalId, SqlDbType.Int);

adapterCustomer.SelectMetadataForCleanupCommand = selMetadataCustomerCmd;
Dim selMetadataCustomerCmd As New SqlCommand()
selMetadataCustomerCmd.CommandType = CommandType.StoredProcedure
selMetadataCustomerCmd.CommandText = "Sync.sp_Customer_SelectMetadata"
selMetadataCustomerCmd.Parameters.Add("@metadata_aging_in_days", SqlDbType.Int).Value = metadataAgingInDays
selMetadataCustomerCmd.Parameters.Add("@" & DbSyncSession.SyncScopeLocalId, SqlDbType.Int)

adapterCustomer.SelectMetadataForCleanupCommand = selMetadataCustomerCmd

L'exemple de code suivant crée la procédure stockée qui est appelée par la commande de nettoyage.

CREATE PROCEDURE Sync.sp_Customer_SelectMetadata     
    @metadata_aging_in_days int,
    @sync_scope_local_id int
AS
    IF @metadata_aging_in_days = -1
        BEGIN
            SELECT  CustomerId,
                    local_update_peer_timestamp as sync_row_timestamp,  
                    case when (update_scope_local_id is null or update_scope_local_id <> @sync_scope_local_id) 
                        then case when (restore_timestamp is null) then local_update_peer_timestamp else restore_timestamp end else scope_update_peer_timestamp end as sync_update_peer_timestamp,
                    case when (update_scope_local_id is null or update_scope_local_id <> @sync_scope_local_id) 
                        then local_update_peer_key else scope_update_peer_key end as sync_update_peer_key,
                    case when (create_scope_local_id is null or create_scope_local_id <> @sync_scope_local_id) 
                        then local_create_peer_timestamp else scope_create_peer_timestamp end as sync_create_peer_timestamp,
                    case when (create_scope_local_id is null or create_scope_local_id <> @sync_scope_local_id) 
                        then local_create_peer_key else scope_create_peer_key end as sync_create_peer_key
            FROM Sync.Customer_Tracking
            WHERE sync_row_is_tombstone = 1
        END
    
    ELSE
        BEGIN
            SELECT  CustomerId,
                    local_update_peer_timestamp as sync_row_timestamp,  
                    case when (update_scope_local_id is null or update_scope_local_id <> @sync_scope_local_id) 
                        then case when (restore_timestamp is null) then local_update_peer_timestamp else restore_timestamp end else scope_update_peer_timestamp end as sync_update_peer_timestamp,
                    case when (update_scope_local_id is null or update_scope_local_id <> @sync_scope_local_id) 
                        then local_update_peer_key else scope_update_peer_key end as sync_update_peer_key,
                    case when (create_scope_local_id is null or create_scope_local_id <> @sync_scope_local_id) 
                        then local_create_peer_timestamp else scope_create_peer_timestamp end as sync_create_peer_timestamp,
                    case when (create_scope_local_id is null or create_scope_local_id <> @sync_scope_local_id) 
                        then local_create_peer_key else scope_create_peer_key end as sync_create_peer_key
            FROM Sync.Customer_Tracking
            WHERE sync_row_is_tombstone = 1 AND
            DATEDIFF(day, last_change_datetime, GETDATE()) > @metadata_aging_in_days
        END

L'exemple de code suivant spécifie une commande pour la propriété SelectOverlappingScopesCommand. Cette commande et la suivante (UpdateScopeCleanupTimestampCommand) permettent à Sync Framework de gérer convenablement le nettoyage lorsqu'une table est incluse dans plusieurs étendues.

SqlCommand overlappingScopesCmd = new SqlCommand();
overlappingScopesCmd.CommandType = CommandType.StoredProcedure;
overlappingScopesCmd.CommandText = "Sync.sp_SelectSharedScopes";
overlappingScopesCmd.Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100);
sampleDbProvider.SelectOverlappingScopesCommand = overlappingScopesCmd;
Dim overlappingScopesCmd As New SqlCommand()
With overlappingScopesCmd
    .CommandType = CommandType.StoredProcedure
    .CommandText = "Sync.sp_SelectSharedScopes"
    .Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100)
End With

sampleDbProvider.SelectOverlappingScopesCommand = overlappingScopesCmd

L'exemple de code suivant crée la procédure stockée qui est appelée par la commande des étendues qui se chevauchent.

CREATE PROCEDURE Sync.sp_SelectSharedScopes
      @sync_scope_name nvarchar(100)      
AS
   SELECT ScopeTableMap2.table_name AS sync_table_name, 
          ScopeTableMap2.scope_name AS sync_shared_scope_name
   FROM Sync.ScopeTableMap ScopeTableMap1 JOIN Sync.ScopeTableMap ScopeTableMap2
   ON ScopeTableMap1.table_name = ScopeTableMap2.table_name
   AND ScopeTableMap1.scope_name = @sync_scope_name
   WHERE ScopeTableMap2.scope_name <> @sync_scope_name

L'exemple de code suivant spécifie une commande pour la propriété UpdateScopeCleanupTimestampCommand.

SqlCommand updScopeCleanupInfoCmd = new SqlCommand();
updScopeCleanupInfoCmd.CommandType = CommandType.Text;
updScopeCleanupInfoCmd.CommandText = "UPDATE  scope_info set " +
                                     " scope_cleanup_timestamp = @" + DbSyncSession.SyncScopeCleanupTimestamp + 
                                     " WHERE scope_name = @" + DbSyncSession.SyncScopeName + 
                                     " AND(scope_cleanup_timestamp is null or scope_cleanup_timestamp <  @" + DbSyncSession.SyncScopeCleanupTimestamp + ");" +
                                     " SET @" + DbSyncSession.SyncRowCount + " = @@rowcount";
updScopeCleanupInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeCleanupTimestamp, SqlDbType.BigInt);
updScopeCleanupInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100);
updScopeCleanupInfoCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;
sampleDbProvider.UpdateScopeCleanupTimestampCommand = updScopeCleanupInfoCmd;
Dim updScopeCleanupInfoCmd As New SqlCommand()
With updScopeCleanupInfoCmd
    .CommandType = CommandType.Text
    .CommandText = "UPDATE  scope_info set " _
                 & " scope_cleanup_timestamp = @" + DbSyncSession.SyncScopeCleanupTimestamp _
                 & " WHERE scope_name = @" + DbSyncSession.SyncScopeName _
                 & " AND(scope_cleanup_timestamp is null or scope_cleanup_timestamp <  @" + DbSyncSession.SyncScopeCleanupTimestamp + ");" _
                 & " SET @" + DbSyncSession.SyncRowCount + " = @@rowcount"
    .Parameters.Add("@" + DbSyncSession.SyncScopeCleanupTimestamp, SqlDbType.BigInt)
    .Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100)
    .Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
End With

sampleDbProvider.UpdateScopeCleanupTimestampCommand = updScopeCleanupInfoCmd

L'exemple de code suivant appelle la méthode CleanupMetadata. Le code instancie un fournisseur et appelle la méthode ConfigureDbSyncProvider dans la classe SampleSyncProvider. Toutes les propriétés DbSyncAdapter et DbSyncProvider requises sont définies dans cette classe. Cela comprend la propriété SelectMetadataForCleanupCommand. La valeur 7 qui est passée à la méthode ConfigureDbSyncProvider correspond à la période de rétention des métadonnées, exprimée en jours.

sampleSyncProvider = new SampleSyncProvider();
DbSyncProvider provider1 = sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync1, 7);

if (provider1.CleanupMetadata() == true)
{
    Console.WriteLine(String.Empty);
    Console.WriteLine("Metadata cleanup ran in the SyncSamplesDb_Peer1 database.");
    Console.WriteLine("Metadata more than 7 days old was deleted.");
}
else
{
    Console.WriteLine("Metadata cleanup failed, most likely due to concurrency issues.");
}
sampleSyncProvider = New SampleSyncProvider()
Dim provider1 As DbSyncProvider = sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync1, 7)

If provider1.CleanupMetadata() = True Then
    Console.WriteLine([String].Empty)
    Console.WriteLine("Metadata cleanup ran in the SyncSamplesDb_Peer1 database.")
    Console.WriteLine("Metadata more than 7 days old was deleted.")
Else
    Console.WriteLine("Metadata cleanup failed, most likely due to concurrency issues.")
End If

Exemple de code complet

L'exemple de code complet ci-dessous inclut les exemples de code décrits précédemment, ainsi que du code supplémentaire pour apporter des modifications et effectuer la synchronisation de ces modifications. Le code effectue les étapes suivantes :

  1. Synchronise SyncSamplesDb_Peer1 (Node1) et SyncSamplesDb_Peer3 (Node3). Cinq lignes sont téléchargées sur Node3.

  2. Synchronise Node3 et SyncSampleCe1 (CeNode1).

  3. Met à jour une ligne sur Node1.

  4. Appelle CleanupMetadata pour les métadonnées qui ont plus de 7 jours sur Node1. La méthode CleanupMetadata est retournée avec succès, mais aucune métadonnée n'est nettoyée, car aucune suppression n'a été effectuée sur Node1 dans les 7 derniers jours.

  5. Synchronise Node1 et Node3. La synchronisation est réussie, car toutes les métadonnées pertinentes sont encore disponibles sur les deux nœuds.

  6. Supprime une ligne de Node3.

  7. Appelle CleanupMetadata pour toutes les métadonnées sur Node3. Les métadonnées pour la suppression de l'étape précédente sont nettoyées.

  8. Synchronise Node1 et Node3. La synchronisation échoue car la connaissance de synchronisation ne correspond plus à l'état du nœud. Une exception de type DbOutdatedSyncException est levée.

Il est important de ne nettoyer que les métadonnées qui ne sont plus requises par d'autres nœuds. Si le deuxième nettoyage s'était produit après réception par Node1 de la suppression de Node3, la synchronisation aurait réussi.

Important

L'exécution de l'exemple de code suivant laisse intentionnellement les exemples de bases de données dans un état incohérent. Après avoir exécuté ce code, supprimez les bases de données et recréez-les en exécutant le script « Suivi des modifications personnalisé pour les scénarios de collaboration » dans Scripts d'installation pour les rubriques de procédures sur le fournisseur de bases de données.

using System;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlServerCe;
using Microsoft.Synchronization;
using Microsoft.Synchronization.Data;
using Microsoft.Synchronization.Data.SqlServerCe;

namespace Microsoft.Samples.Synchronization
{
    class Program
    {
        static void Main(string[] args)
        {

            //The Utility class handles all functionality that is not
            //directly related to synchronization, such as holding peerConnection 
            //string information and making changes to the server database.
            Utility.DeleteAndRecreateCompactDatabase(Utility.ConnStr_SqlCeSync1, true);

            //The SampleStats class handles information from the SyncStatistics
            //object that the Synchronize method returns.
            SampleStats sampleStats = new SampleStats();
            SampleSyncProvider sampleSyncProvider = new SampleSyncProvider();

            try
            {
                //Initial synchronization. Instantiate the SyncOrchestrator
                //and call Synchronize.    
                sampleSyncProvider = new SampleSyncProvider();
                SyncOrchestrator sampleSyncAgent;
                SyncOperationStatistics syncStatistics;

                //The integer passed to ConfigureDbSyncProvider is how old that metadata
                //can be (in days) before it is deleted when CleanupMetadata() is called.
                //The integer value is only relevant if CleanupMetadata() is called, as
                //demonstrated later in this application.
                sampleSyncAgent = new SampleSyncAgent(
                                        sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync1, 7),
                                        sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync3, 7));
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "initial");

                sampleSyncAgent = new SampleSyncAgent(
                        sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync3, 7),
                        sampleSyncProvider.ConfigureCeSyncProvider(Utility.ConnStr_SqlCeSync1));
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "initial");
            }


            catch (DbOutdatedSyncException ex)
            {
                Console.WriteLine("Outdated Knowledge: " + ex.OutdatedPeerSyncKnowledge.ToString() +
                                  " Clean up knowledge: " + ex.MissingCleanupKnowledge.ToString());
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }


            //Update a row on peer 1.
            Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync1, "Customer");


            //Instantiate a provider, connect to peer 1, and delete tombstone metadata that
            //is older than 7 days.
            sampleSyncProvider = new SampleSyncProvider();
            DbSyncProvider provider1 = sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync1, 7);

            if (provider1.CleanupMetadata() == true)
            {
                Console.WriteLine(String.Empty);
                Console.WriteLine("Metadata cleanup ran in the SyncSamplesDb_Peer1 database.");
                Console.WriteLine("Metadata more than 7 days old was deleted.");
            }
            else
            {
                Console.WriteLine("Metadata cleanup failed, most likely due to concurrency issues.");
            }

            //Synchronize.
            try
            {
                SyncOrchestrator sampleSyncAgent;
                SyncOperationStatistics syncStatistics;

                sampleSyncAgent = new SampleSyncAgent(
                                        sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync1, 7),
                                        sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync3, 7));
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "subsequent");
            }


            catch (DbOutdatedSyncException ex)
            {

                Console.WriteLine("Outdated Knowledge: " + ex.OutdatedPeerSyncKnowledge.ToString() +
                                  " Clean up knowledge: " + ex.MissingCleanupKnowledge.ToString());

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }


            //Delete a row on peer 3.
            Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync3, "Customer");


            //Instantiate a provider, connect to peer 3, and delete all tombstone metadata.
            sampleSyncProvider = new SampleSyncProvider();
            DbSyncProvider provider3 = sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync3, -1);


            if (provider3.CleanupMetadata() == true)
            {
                Console.WriteLine(String.Empty);
                Console.WriteLine("Metadata cleanup ran in the SyncSamplesDb_Peer3 database.");
                Console.WriteLine("All metadata was deleted.");
            }
            else
            {
                Console.WriteLine("Metadata cleanup failed, most likely due to concurrency issues.");
            }


            //Synchronize.
            try
            {
                SyncOrchestrator sampleSyncAgent;
                SyncOperationStatistics syncStatistics;

                sampleSyncAgent = new SampleSyncAgent(
                                        sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync1, 7),
                                        sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync3, 7));
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "subsequent");
            }


            catch (DbOutdatedSyncException ex)
            {

                Console.WriteLine(String.Empty);
                Console.WriteLine("Synchronization failed due to outdated synchronization knowledge,");
                Console.WriteLine("which is expected in this sample application.");
                Console.WriteLine("Drop and recreate the sample databases.");
                Console.WriteLine(String.Empty);
                Console.WriteLine("Outdated Knowledge: " + ex.OutdatedPeerSyncKnowledge.ToString() +
                                  " Clean up knowledge: " + ex.MissingCleanupKnowledge.ToString());
                Console.WriteLine(String.Empty);

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

            //Return peer data back to its original state.
            Utility.CleanUpNode(Utility.ConnStr_DbSync1);
            Utility.CleanUpNode(Utility.ConnStr_DbSync3);

            //Exit.
            Console.Write("\nPress Enter to close the window.");
            Console.ReadLine();
        }
    }

    //Create a class that is derived from 
    //Microsoft.Synchronization.SyncOrchestrator.
    public class SampleSyncAgent : SyncOrchestrator
    {
        public SampleSyncAgent(RelationalSyncProvider localProvider, RelationalSyncProvider remoteProvider)
        {

            this.LocalProvider = localProvider;
            this.RemoteProvider = remoteProvider;
            this.Direction = SyncDirectionOrder.UploadAndDownload;

            //Check to see if any provider is a SqlCe provider and if it needs to
            //be initialized.
            CheckIfProviderNeedsSchema(localProvider as SqlCeSyncProvider, remoteProvider as DbSyncProvider);
            CheckIfProviderNeedsSchema(remoteProvider as SqlCeSyncProvider, localProvider as DbSyncProvider);
        }

        //For Compact databases that are not initialized with a snapshot,
        //get the schema and initial data from a server database.
        private void CheckIfProviderNeedsSchema(SqlCeSyncProvider providerToCheck, DbSyncProvider providerWithSchema)
        {

            //If one of the providers is a SqlCeSyncProvider and it needs
            //to be initialized, retrieve the schema from the other provider
            //if that provider is a DbSyncProvider; otherwise configure a
            //DbSyncProvider, connect to the server, and retrieve the schema.
            if (providerToCheck != null)
            {
                SqlCeConnection ceConn = (SqlCeConnection)providerToCheck.Connection;
                SqlCeSyncScopeProvisioning ceConfig = new SqlCeSyncScopeProvisioning(ceConn);
                string scopeName = providerToCheck.ScopeName;
                if (!ceConfig.ScopeExists(scopeName))
                {
                    DbSyncScopeDescription scopeDesc = providerWithSchema.GetScopeDescription();
                    ceConfig.PopulateFromScopeDescription(scopeDesc);
                    ceConfig.Apply();
                }
            }

        }

    }

    public class SampleSyncProvider
    {

        public SqlCeSyncProvider ConfigureCeSyncProvider(string sqlCeConnString)
        {

            SqlCeSyncProvider sampleCeProvider = new SqlCeSyncProvider();

            //Set the scope name
            sampleCeProvider.ScopeName = "Sales";

            //Set the connection
            sampleCeProvider.Connection = new SqlCeConnection(sqlCeConnString);

            return sampleCeProvider;
        }


        public DbSyncProvider ConfigureDbSyncProvider(string peerConnString, int metadataAgingInDays)
        {

            DbSyncProvider sampleDbProvider = new DbSyncProvider();

            SqlConnection peerConnection = new SqlConnection(peerConnString);
            sampleDbProvider.Connection = peerConnection;
            sampleDbProvider.ScopeName = "Sales";

            //Create a DbSyncAdapter object for the Customer table and associate it 
            //with the DbSyncProvider. Following the DataAdapter style in ADO.NET, 
            //DbSyncAdapter is the equivalent for synchronization. The commands that 
            //are specified for the DbSyncAdapter object call stored procedures
            //that are created in each peer database.
            DbSyncAdapter adapterCustomer = new DbSyncAdapter("Customer");


            //Specify the primary key, which Sync Framework uses
            //to identify each row during synchronization.
            adapterCustomer.RowIdColumns.Add("CustomerId");


            //Specify the command to select incremental changes.
            //In this command and other commands, session variables are
            //used to pass information at runtime. DbSyncSession.SyncMetadataOnly 
            //and SyncMinTimestamp are two of the string constants that
            //the DbSyncSession class exposes. You could also include 
            //@sync_metadata_only and @sync_min_timestamp directly in your 
            //queries:
            //*  sync_metadata_only is used by Sync Framework as an optimization
            //   in some queries.
            //* The value of the sync_min_timestamp session variable is compared to
            //   values in the sync_row_timestamp column in the tracking table to 
            //   determine which rows to select.
            SqlCommand chgsCustomerCmd = new SqlCommand();
            chgsCustomerCmd.CommandType = CommandType.StoredProcedure;
            chgsCustomerCmd.CommandText = "Sync.sp_Customer_SelectChanges";
            chgsCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncMetadataOnly, SqlDbType.Int);
            chgsCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncMinTimestamp, SqlDbType.BigInt);
            chgsCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncScopeLocalId, SqlDbType.Int);
            chgsCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncInitialize, SqlDbType.Int);

            adapterCustomer.SelectIncrementalChangesCommand = chgsCustomerCmd;

            //Specify the command to insert rows.
            //The sync_row_count session variable is used in this command 
            //and other commands to return a count of the rows affected by an operation. 
            //A count of 0 indicates that an operation failed.
            SqlCommand insCustomerCmd = new SqlCommand();
            insCustomerCmd.CommandType = CommandType.StoredProcedure;
            insCustomerCmd.CommandText = "Sync.sp_Customer_ApplyInsert";
            insCustomerCmd.Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier);
            insCustomerCmd.Parameters.Add("@CustomerName", SqlDbType.NVarChar);
            insCustomerCmd.Parameters.Add("@SalesPerson", SqlDbType.NVarChar);
            insCustomerCmd.Parameters.Add("@CustomerType", SqlDbType.NVarChar);
            insCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;

            adapterCustomer.InsertCommand = insCustomerCmd;


            //Specify the command to update rows.
            //The value of the sync_min_timestamp session variable is compared to
            //values in the sync_row_timestamp column in the tracking table to 
            //determine which rows to update.
            SqlCommand updCustomerCmd = new SqlCommand();
            updCustomerCmd.CommandType = CommandType.StoredProcedure;
            updCustomerCmd.CommandText = "Sync.sp_Customer_ApplyUpdate";
            updCustomerCmd.Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier);
            updCustomerCmd.Parameters.Add("@CustomerName", SqlDbType.NVarChar);
            updCustomerCmd.Parameters.Add("@SalesPerson", SqlDbType.NVarChar);
            updCustomerCmd.Parameters.Add("@CustomerType", SqlDbType.NVarChar);
            updCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncMinTimestamp, SqlDbType.BigInt);
            updCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;
            updCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncForceWrite, SqlDbType.Int);

            adapterCustomer.UpdateCommand = updCustomerCmd;


            //Specify the command to delete rows.
            //The value of the sync_min_timestamp session variable is compared to
            //values in the sync_row_timestamp column in the tracking table to 
            //determine which rows to delete.
            SqlCommand delCustomerCmd = new SqlCommand();
            delCustomerCmd.CommandType = CommandType.StoredProcedure;
            delCustomerCmd.CommandText = "Sync.sp_Customer_ApplyDelete";
            delCustomerCmd.Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier);
            delCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncMinTimestamp, SqlDbType.BigInt);
            delCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;
            delCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncForceWrite, SqlDbType.Int);

            adapterCustomer.DeleteCommand = delCustomerCmd;

            //Specify the command to select any conflicting rows.
            SqlCommand selRowCustomerCmd = new SqlCommand();
            selRowCustomerCmd.CommandType = CommandType.StoredProcedure;
            selRowCustomerCmd.CommandText = "Sync.sp_Customer_SelectRow";
            selRowCustomerCmd.Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier);
            selRowCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncScopeLocalId, SqlDbType.Int);

            adapterCustomer.SelectRowCommand = selRowCustomerCmd;


            //Specify the command to insert metadata rows.
            //The session variables in this command relate to columns in
            //the tracking table.
            SqlCommand insMetadataCustomerCmd = new SqlCommand();
            insMetadataCustomerCmd.CommandType = CommandType.StoredProcedure;
            insMetadataCustomerCmd.CommandText = "Sync.sp_Customer_InsertMetadata";
            insMetadataCustomerCmd.Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncScopeLocalId, SqlDbType.Int);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowTimestamp, SqlDbType.BigInt);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncCreatePeerKey, SqlDbType.Int);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncCreatePeerTimestamp, SqlDbType.BigInt);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncUpdatePeerKey, SqlDbType.Int);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncUpdatePeerTimestamp, SqlDbType.BigInt);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowIsTombstone, SqlDbType.Int);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncCheckConcurrency, SqlDbType.Int);
            insMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;

            adapterCustomer.InsertMetadataCommand = insMetadataCustomerCmd;


            //Specify the command to update metadata rows.
            SqlCommand updMetadataCustomerCmd = new SqlCommand();
            updMetadataCustomerCmd.CommandType = CommandType.StoredProcedure;
            updMetadataCustomerCmd.CommandText = "Sync.sp_Customer_UpdateMetadata";
            updMetadataCustomerCmd.Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncScopeLocalId, SqlDbType.Int);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowTimestamp, SqlDbType.BigInt);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncCreatePeerKey, SqlDbType.Int);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncCreatePeerTimestamp, SqlDbType.BigInt);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncUpdatePeerKey, SqlDbType.Int);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncUpdatePeerTimestamp, SqlDbType.BigInt);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowIsTombstone, SqlDbType.Int);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncCheckConcurrency, SqlDbType.Int);
            updMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;

            adapterCustomer.UpdateMetadataCommand = updMetadataCustomerCmd;

            //Specify the command to delete metadata rows.
            SqlCommand delMetadataCustomerCmd = new SqlCommand();
            delMetadataCustomerCmd.CommandType = CommandType.StoredProcedure;
            delMetadataCustomerCmd.CommandText = "Sync.sp_Customer_DeleteMetadata";
            delMetadataCustomerCmd.Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier);
            delMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncCheckConcurrency, SqlDbType.Int);
            delMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowTimestamp, SqlDbType.BigInt);
            delMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;

            adapterCustomer.DeleteMetadataCommand = delMetadataCustomerCmd;

            //Specify the command to select metadata rows for cleanup.
            SqlCommand selMetadataCustomerCmd = new SqlCommand();
            selMetadataCustomerCmd.CommandType = CommandType.StoredProcedure;
            selMetadataCustomerCmd.CommandText = "Sync.sp_Customer_SelectMetadata";
            selMetadataCustomerCmd.Parameters.Add("@metadata_aging_in_days", SqlDbType.Int).Value = metadataAgingInDays;
            selMetadataCustomerCmd.Parameters.Add("@" + DbSyncSession.SyncScopeLocalId, SqlDbType.Int);

            adapterCustomer.SelectMetadataForCleanupCommand = selMetadataCustomerCmd;

            //Add the adapter to the provider.
            sampleDbProvider.SyncAdapters.Add(adapterCustomer);


            // Configure commands that relate to the provider itself rather 
            // than the DbSyncAdapter object for each table:
            // * SelectNewTimestampCommand: Returns the new high watermark for 
            //   the current synchronization session.
            // * SelectScopeInfoCommand: Returns sync knowledge, cleanup knowledge, 
            //   and a scope version (timestamp).
            // * UpdateScopeInfoCommand: Sets new values for sync knowledge and cleanup knowledge.            
            // * SelectTableMaxTimestampsCommand (optional): Returns the maximum timestamp from each base table 
            //   or tracking table, to determine whether for each table the destination already 
            //   has all of the changes from the source. If a destination table has all the changes,
            //   SelectIncrementalChangesCommand is not called for that table.
            // * SelectOverlappingScopesCommand: returns the scope name and table name for all tables 
            //   in the specified scope that are also included in other scopes.
            // * UpdateScopeCleanupTimestampCommand: updates the scope_cleanup_timestamp column for a 
            //   particular scope in the scope_info table, to mark the point up to which cleanup 
            //   has been performed for the scope.


            //Select a new timestamp.
            //During each synchronization, the new value and
            //the last value from the previous synchronization
            //are used: the set of changes between these upper and
            //lower bounds is synchronized.
            SqlCommand selectNewTimestampCommand = new SqlCommand();
            string newTimestampVariable = "@" + DbSyncSession.SyncNewTimestamp;
            selectNewTimestampCommand.CommandText = "SELECT " + newTimestampVariable + " = min_active_rowversion() - 1";
            selectNewTimestampCommand.Parameters.Add(newTimestampVariable, SqlDbType.Timestamp);
            selectNewTimestampCommand.Parameters[newTimestampVariable].Direction = ParameterDirection.Output;

            sampleDbProvider.SelectNewTimestampCommand = selectNewTimestampCommand;

            //Specify the command to select local replica metadata.
            SqlCommand selReplicaInfoCmd = new SqlCommand();
            selReplicaInfoCmd.CommandType = CommandType.Text;
            selReplicaInfoCmd.CommandText = "SELECT " +
                                            "scope_id, " +
                                            "scope_local_id, " +
                                            "scope_sync_knowledge, " +
                                            "scope_tombstone_cleanup_knowledge, " +
                                            "scope_timestamp " +
                                            "FROM Sync.ScopeInfo " +
                                            "WHERE scope_name = @" + DbSyncSession.SyncScopeName;
            selReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100);

            sampleDbProvider.SelectScopeInfoCommand = selReplicaInfoCmd;


            //Specify the command to update local replica metadata. 
            SqlCommand updReplicaInfoCmd = new SqlCommand();
            updReplicaInfoCmd.CommandType = CommandType.Text;
            updReplicaInfoCmd.CommandText = "UPDATE  Sync.ScopeInfo SET " +
                                            "scope_sync_knowledge = @" + DbSyncSession.SyncScopeKnowledge + ", " +
                                            "scope_id = @" + DbSyncSession.SyncScopeId + ", " +
                                            "scope_tombstone_cleanup_knowledge = @" + DbSyncSession.SyncScopeCleanupKnowledge + " " +
                                            "WHERE scope_name = @" + DbSyncSession.SyncScopeName + " AND " +
                                            " ( @" + DbSyncSession.SyncCheckConcurrency + " = 0 OR scope_timestamp = @" + DbSyncSession.SyncScopeTimestamp + "); " +
                                            "SET @" + DbSyncSession.SyncRowCount + " = @@rowcount";
            updReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeKnowledge, SqlDbType.VarBinary, 10000);
            updReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeCleanupKnowledge, SqlDbType.VarBinary, 10000);
            updReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100);
            updReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncCheckConcurrency, SqlDbType.Int);
            updReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeId, SqlDbType.UniqueIdentifier);
            updReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeTimestamp, SqlDbType.BigInt);
            updReplicaInfoCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;

            sampleDbProvider.UpdateScopeInfoCommand = updReplicaInfoCmd;


            //Return the maximum timestamp from the Customer_Tracking table.
            //If more tables are synchronized, the query should UNION
            //all of the results. The table name is not schema-qualified
            //in this case because the name was not schema qualified in the
            //DbSyncAdapter constructor.
            SqlCommand selTableMaxTsCmd = new SqlCommand();
            selTableMaxTsCmd.CommandType = CommandType.Text;
            selTableMaxTsCmd.CommandText = "SELECT 'Customer' AS table_name, " +
                                           "MAX(local_update_peer_timestamp) AS max_timestamp " +
                                           "FROM Sync.Customer_Tracking";
            sampleDbProvider.SelectTableMaxTimestampsCommand = selTableMaxTsCmd;


            //Specify the command to select table and scope names for
            //any tables that are in more than one scope.
            SqlCommand overlappingScopesCmd = new SqlCommand();
            overlappingScopesCmd.CommandType = CommandType.StoredProcedure;
            overlappingScopesCmd.CommandText = "Sync.sp_SelectSharedScopes";
            overlappingScopesCmd.Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100);
            sampleDbProvider.SelectOverlappingScopesCommand = overlappingScopesCmd;

            //Specify the command that updates the scope information table
            //to indicate to which point metadata has been cleaned up for a scope.
            SqlCommand updScopeCleanupInfoCmd = new SqlCommand();
            updScopeCleanupInfoCmd.CommandType = CommandType.Text;
            updScopeCleanupInfoCmd.CommandText = "UPDATE  scope_info set " +
                                                 " scope_cleanup_timestamp = @" + DbSyncSession.SyncScopeCleanupTimestamp + 
                                                 " WHERE scope_name = @" + DbSyncSession.SyncScopeName + 
                                                 " AND(scope_cleanup_timestamp is null or scope_cleanup_timestamp <  @" + DbSyncSession.SyncScopeCleanupTimestamp + ");" +
                                                 " SET @" + DbSyncSession.SyncRowCount + " = @@rowcount";
            updScopeCleanupInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeCleanupTimestamp, SqlDbType.BigInt);
            updScopeCleanupInfoCmd.Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100);
            updScopeCleanupInfoCmd.Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output;
            sampleDbProvider.UpdateScopeCleanupTimestampCommand = updScopeCleanupInfoCmd;

            return sampleDbProvider;

        }
    }

    //Handle the statistics that are returned by the SyncAgent.
    public class SampleStats
    {
        public void DisplayStats(SyncOperationStatistics syncStatistics, string syncType)
        {
            Console.WriteLine(String.Empty);
            if (syncType == "initial")
            {
                Console.WriteLine("****** Initial Synchronization ******");
            }
            else if (syncType == "subsequent")
            {
                Console.WriteLine("***** Subsequent Synchronization ****");
            }

            Console.WriteLine("Start Time: " + syncStatistics.SyncStartTime);
            Console.WriteLine("Total Changes Uploaded: " + syncStatistics.UploadChangesTotal);
            Console.WriteLine("Total Changes Downloaded: " + syncStatistics.DownloadChangesTotal);
            Console.WriteLine("Complete Time: " + syncStatistics.SyncEndTime);
            Console.WriteLine(String.Empty);
        }
    }
}
Imports System
Imports System.IO
Imports System.Collections.Generic
Imports System.Text
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.SqlServerCe
Imports Microsoft.Synchronization
Imports Microsoft.Synchronization.Data
Imports Microsoft.Synchronization.Data.SqlServerCe

Class Program
    Shared Sub Main(ByVal args As String())

        'The Utility class handles all functionality that is not 
        'directly related to synchronization, such as holding peerConnection 
        'string information and making changes to the server database. 
        Utility.DeleteAndRecreateCompactDatabase(Utility.ConnStr_SqlCeSync1, True)

        'The SampleStats class handles information from the SyncStatistics 
        'object that the Synchronize method returns. 
        Dim sampleStats As New SampleStats()
        Dim sampleSyncProvider As New SampleSyncProvider()

        Try
            'Initial synchronization. Instantiate the SyncOrchestrator 
            'and call Synchronize. 
            sampleSyncProvider = New SampleSyncProvider()
            Dim sampleSyncAgent As SyncOrchestrator
            Dim syncStatistics As SyncOperationStatistics

            'The integer passed to ConfigureDbSyncProvider is how old that metadata 
            'can be (in days) before it is deleted when CleanupMetadata() is called. 
            'The integer value is only relevant if CleanupMetadata() is called, as 
            'demonstrated later in this application. 
            sampleSyncAgent = New SampleSyncAgent(sampleSyncProvider.ConfigureDbSyncProvider( _
                                                  Utility.ConnStr_DbSync1, 7), _
                                                  sampleSyncProvider.ConfigureDbSyncProvider( _
                                                  Utility.ConnStr_DbSync3, 7))
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "initial")

            sampleSyncAgent = New SampleSyncAgent(sampleSyncProvider.ConfigureDbSyncProvider( _
                                                  Utility.ConnStr_DbSync3, 7), _
                                                  sampleSyncProvider.ConfigureCeSyncProvider( _
                                                  Utility.ConnStr_SqlCeSync1))
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "initial")
        Catch ex As DbOutdatedSyncException


            Console.WriteLine(("Outdated Knowledge: " & ex.OutdatedPeerSyncKnowledge.ToString() _
                               & " Clean up knowledge: ") + ex.MissingCleanupKnowledge.ToString())
        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try


        'Update a row on peer 1. 
        Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync1, "Customer")


        'Instantiate a provider, connect to peer 1, and delete tombstone metadata that 
        'is older than 7 days. 
        sampleSyncProvider = New SampleSyncProvider()
        Dim provider1 As DbSyncProvider = sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync1, 7)

        If provider1.CleanupMetadata() = True Then
            Console.WriteLine([String].Empty)
            Console.WriteLine("Metadata cleanup ran in the SyncSamplesDb_Peer1 database.")
            Console.WriteLine("Metadata more than 7 days old was deleted.")
        Else
            Console.WriteLine("Metadata cleanup failed, most likely due to concurrency issues.")
        End If

        'Synchronize. 
        Try
            Dim sampleSyncAgent As SyncOrchestrator
            Dim syncStatistics As SyncOperationStatistics

            sampleSyncAgent = New SampleSyncAgent(sampleSyncProvider.ConfigureDbSyncProvider( _
                                                  Utility.ConnStr_DbSync1, 7), _
                                                  sampleSyncProvider.ConfigureDbSyncProvider( _
                                                  Utility.ConnStr_DbSync3, 7))
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "subsequent")
        Catch ex As DbOutdatedSyncException



            Console.WriteLine(("Outdated Knowledge: " & ex.OutdatedPeerSyncKnowledge.ToString() _
                               & " Clean up knowledge: ") + ex.MissingCleanupKnowledge.ToString())

        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try


        'Delete a row on peer 3. 
        Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync3, "Customer")


        'Instantiate a provider, connect to peer 3, and delete all tombstone metadata. 
        sampleSyncProvider = New SampleSyncProvider()
        Dim provider3 As DbSyncProvider = sampleSyncProvider.ConfigureDbSyncProvider(Utility.ConnStr_DbSync3, -1)


        If provider3.CleanupMetadata() = True Then
            Console.WriteLine([String].Empty)
            Console.WriteLine("Metadata cleanup ran in the SyncSamplesDb_Peer3 database.")
            Console.WriteLine("All metadata was deleted.")
        Else
            Console.WriteLine("Metadata cleanup failed, most likely due to concurrency issues.")
        End If


        'Synchronize. 
        Try
            Dim sampleSyncAgent As SyncOrchestrator
            Dim syncStatistics As SyncOperationStatistics

            sampleSyncAgent = New SampleSyncAgent(sampleSyncProvider.ConfigureDbSyncProvider( _
                                                  Utility.ConnStr_DbSync1, 7), _
                                                  sampleSyncProvider.ConfigureDbSyncProvider( _
                                                  Utility.ConnStr_DbSync3, 7))
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "subsequent")
        Catch ex As DbOutdatedSyncException



            Console.WriteLine([String].Empty)
            Console.WriteLine("Synchronization failed due to outdated synchronization knowledge,")
            Console.WriteLine("which is expected in this sample application.")
            Console.WriteLine("Drop and recreate the sample databases.")
            Console.WriteLine([String].Empty)
            Console.WriteLine(("Outdated Knowledge: " & ex.OutdatedPeerSyncKnowledge.ToString() _
                               & " Clean up knowledge: ") + ex.MissingCleanupKnowledge.ToString())
            Console.WriteLine([String].Empty)

        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try

        'Return peer data back to its original state. 
        Utility.CleanUpNode(Utility.ConnStr_DbSync1)
        Utility.CleanUpNode(Utility.ConnStr_DbSync3)

        'Exit. 
        Console.Write(vbLf & "Press Enter to close the window.")
        Console.ReadLine()
    End Sub
End Class

'Create a class that is derived from 
'Microsoft.Synchronization.SyncOrchestrator. 
Public Class SampleSyncAgent
    Inherits SyncOrchestrator
    Public Sub New(ByVal localProvider As RelationalSyncProvider, ByVal _
                   remoteProvider As RelationalSyncProvider)

        Me.LocalProvider = localProvider
        Me.RemoteProvider = remoteProvider
        Me.Direction = SyncDirectionOrder.UploadAndDownload

        'Check to see if any provider is a SqlCe provider and if it needs to 
        'be initialized. 
        CheckIfProviderNeedsSchema(TryCast(localProvider, SqlCeSyncProvider), _
                                   TryCast(remoteProvider, DbSyncProvider))
        CheckIfProviderNeedsSchema(TryCast(remoteProvider, SqlCeSyncProvider), _
                                   TryCast(localProvider, DbSyncProvider))
    End Sub

    'For Compact databases that are not initialized with a snapshot, 
    'get the schema and initial data from a server database. 
    Private Sub CheckIfProviderNeedsSchema(ByVal providerToCheck As SqlCeSyncProvider, _
                                           ByVal providerWithSchema As DbSyncProvider)

        'If one of the providers is a SqlCeSyncProvider and it needs 
        'to be initialized, retrieve the schema from the other provider 
        'if that provider is a DbSyncProvider; otherwise configure a 
        'DbSyncProvider, connect to the server, and retrieve the schema. 
        If providerToCheck IsNot Nothing Then
            Dim ceConn As SqlCeConnection = DirectCast(providerToCheck.Connection, SqlCeConnection)
            Dim ceConfig As New SqlCeSyncScopeProvisioning(ceConn)
            Dim scopeName As String = providerToCheck.ScopeName
            If Not ceConfig.ScopeExists(scopeName) Then
                Dim scopeDesc As DbSyncScopeDescription = providerWithSchema.GetScopeDescription()
                ceConfig.PopulateFromScopeDescription(scopeDesc)
                ceConfig.Apply()
            End If

        End If

    End Sub
End Class


Public Class SampleSyncProvider

    Public Function ConfigureCeSyncProvider(ByVal sqlCeConnString As String) As SqlCeSyncProvider

        Dim sampleCeProvider As New SqlCeSyncProvider()

        'Set the scope name 
        sampleCeProvider.ScopeName = "Sales"

        'Set the connection 
        sampleCeProvider.Connection = New SqlCeConnection(sqlCeConnString)

        Return sampleCeProvider
    End Function


    Public Function ConfigureDbSyncProvider(ByVal peerConnString As String, ByVal metadataAgingInDays As Integer) As DbSyncProvider

        Dim sampleDbProvider As New DbSyncProvider()

        Dim peerConnection As New SqlConnection(peerConnString)
        sampleDbProvider.Connection = peerConnection
        sampleDbProvider.ScopeName = "Sales"

        'Create a DbSyncAdapter object for the Customer table and associate it 
        'with the DbSyncProvider. Following the DataAdapter style in ADO.NET, 
        'DbSyncAdapter is the equivalent for synchronization. The commands that 
        'are specified for the DbSyncAdapter object call stored procedures 
        'that are created in each peer database. 
        Dim adapterCustomer As New DbSyncAdapter("Customer")


        'Specify the primary key, which Sync Framework uses 
        'to identify each row during synchronization. 
        adapterCustomer.RowIdColumns.Add("CustomerId")


        'Specify the command to select incremental changes. 
        'In this command and other commands, session variables are 
        'used to pass information at runtime. DbSyncSession.SyncMetadataOnly 
        'and SyncMinTimestamp are two of the string constants that 
        'the DbSyncSession class exposes. You could also include 
        '@sync_metadata_only and @sync_min_timestamp directly in your 
        'queries: 
        '* sync_metadata_only is used by Sync Framework as an optimization 
        ' in some queries. 
        '* The value of the sync_min_timestamp session variable is compared to 
        ' values in the sync_row_timestamp column in the tracking table to 
        ' determine which rows to select. 
        Dim chgsCustomerCmd As New SqlCommand()
        With chgsCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_SelectChanges"
            .Parameters.Add("@" & DbSyncSession.SyncMetadataOnly, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncMinTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncScopeLocalId, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncInitialize, SqlDbType.Int)
        End With

        adapterCustomer.SelectIncrementalChangesCommand = chgsCustomerCmd

        'Specify the command to insert rows. 
        'The sync_row_count session variable is used in this command 
        'and other commands to return a count of the rows affected by an operation. 
        'A count of 0 indicates that an operation failed. 
        Dim insCustomerCmd As New SqlCommand()
        With insCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_ApplyInsert"
            .Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier)
            .Parameters.Add("@CustomerName", SqlDbType.NVarChar)
            .Parameters.Add("@SalesPerson", SqlDbType.NVarChar)
            .Parameters.Add("@CustomerType", SqlDbType.NVarChar)
            .Parameters.Add("@" & DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
        End With

        adapterCustomer.InsertCommand = insCustomerCmd


        'Specify the command to update rows. 
        'The value of the sync_min_timestamp session variable is compared to 
        'values in the sync_row_timestamp column in the tracking table to 
        'determine which rows to update. 
        Dim updCustomerCmd As New SqlCommand()
        With updCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_ApplyUpdate"
            .Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier)
            .Parameters.Add("@CustomerName", SqlDbType.NVarChar)
            .Parameters.Add("@SalesPerson", SqlDbType.NVarChar)
            .Parameters.Add("@CustomerType", SqlDbType.NVarChar)
            .Parameters.Add("@" & DbSyncSession.SyncMinTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
            .Parameters.Add("@" & DbSyncSession.SyncForceWrite, SqlDbType.Int)
        End With

        adapterCustomer.UpdateCommand = updCustomerCmd


        'Specify the command to delete rows. 
        'The value of the sync_min_timestamp session variable is compared to 
        'values in the sync_row_timestamp column in the tracking table to 
        'determine which rows to delete. 
        Dim delCustomerCmd As New SqlCommand()
        With delCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_ApplyDelete"
            .Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier)
            .Parameters.Add("@" & DbSyncSession.SyncMinTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
            .Parameters.Add("@" & DbSyncSession.SyncForceWrite, SqlDbType.Int)
        End With

        adapterCustomer.DeleteCommand = delCustomerCmd

        'Specify the command to select any conflicting rows. 
        Dim selRowCustomerCmd As New SqlCommand()
        With selRowCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_SelectRow"
            .Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier)
            .Parameters.Add("@" & DbSyncSession.SyncScopeLocalId, SqlDbType.Int)
        End With

        adapterCustomer.SelectRowCommand = selRowCustomerCmd


        'Specify the command to insert metadata rows. 
        'The session variables in this command relate to columns in 
        'the tracking table. 
        Dim insMetadataCustomerCmd As New SqlCommand()
        With insMetadataCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_InsertMetadata"
            .Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier)
            .Parameters.Add("@" & DbSyncSession.SyncScopeLocalId, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncRowTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncCreatePeerKey, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncCreatePeerTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncUpdatePeerKey, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncUpdatePeerTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncRowIsTombstone, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncCheckConcurrency, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
        End With

        adapterCustomer.InsertMetadataCommand = insMetadataCustomerCmd


        'Specify the command to update metadata rows. 
        Dim updMetadataCustomerCmd As New SqlCommand()
        With updMetadataCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_UpdateMetadata"
            .Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier)
            .Parameters.Add("@" & DbSyncSession.SyncScopeLocalId, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncRowTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncCreatePeerKey, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncCreatePeerTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncUpdatePeerKey, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncUpdatePeerTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncRowIsTombstone, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncCheckConcurrency, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
        End With

        adapterCustomer.UpdateMetadataCommand = updMetadataCustomerCmd

        'Specify the command to delete metadata rows. 
        Dim delMetadataCustomerCmd As New SqlCommand()
        With delMetadataCustomerCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_Customer_DeleteMetadata"
            .Parameters.Add("@CustomerId", SqlDbType.UniqueIdentifier)
            .Parameters.Add("@" & DbSyncSession.SyncCheckConcurrency, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncRowTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
        End With

        adapterCustomer.DeleteMetadataCommand = delMetadataCustomerCmd


        'Specify the command to select metadata rows for cleanup. 
        Dim selMetadataCustomerCmd As New SqlCommand()
        selMetadataCustomerCmd.CommandType = CommandType.StoredProcedure
        selMetadataCustomerCmd.CommandText = "Sync.sp_Customer_SelectMetadata"
        selMetadataCustomerCmd.Parameters.Add("@metadata_aging_in_days", SqlDbType.Int).Value = metadataAgingInDays
        selMetadataCustomerCmd.Parameters.Add("@" & DbSyncSession.SyncScopeLocalId, SqlDbType.Int)

        adapterCustomer.SelectMetadataForCleanupCommand = selMetadataCustomerCmd


        'Add the adapter to the provider. 
        sampleDbProvider.SyncAdapters.Add(adapterCustomer)


        ' Configure commands that relate to the provider itself rather 
        ' than the DbSyncAdapter object for each table: 
        ' * SelectNewTimestampCommand: Returns the new high watermark for 
        ' the current synchronization session. 
        ' * SelectScopeInfoCommand: Returns sync knowledge, cleanup knowledge, 
        ' and a scope version (timestamp). 
        ' * UpdateScopeInfoCommand: Sets new values for sync knowledge and cleanup knowledge. 
        ' * SelectTableMaxTimestampsCommand (optional): Returns the maximum timestamp from each base table 
        ' or tracking table, to determine whether for each table the destination already 
        ' has all of the changes from the source. If a destination table has all the changes, 
        ' SelectIncrementalChangesCommand is not called for that table. 
        ' * SelectOverlappingScopesCommand: returns the scope name and table name for all tables 
        '   in the specified scope that are also included in other scopes.
        ' * UpdateScopeCleanupTimestampCommand: updates the scope_cleanup_timestamp column for a 
        '   particular scope in the scope_info table, to mark the point up to which cleanup 
        '   has been performed for the scope.


        'Select a new timestamp. 
        'During each synchronization, the new value and 
        'the last value from the previous synchronization 
        'are used: the set of changes between these upper and 
        'lower bounds is synchronized. 
        Dim selectNewTimestampCommand As New SqlCommand()
        Dim newTimestampVariable As String = "@" & DbSyncSession.SyncNewTimestamp
        With selectNewTimestampCommand
            .CommandText = "SELECT " & newTimestampVariable & " = min_active_rowversion() - 1"
            .Parameters.Add(newTimestampVariable, SqlDbType.Timestamp)
            .Parameters(newTimestampVariable).Direction = ParameterDirection.Output
        End With

        sampleDbProvider.SelectNewTimestampCommand = selectNewTimestampCommand

        'Specify the command to select local replica metadata. 
        Dim selReplicaInfoCmd As New SqlCommand()
        With selReplicaInfoCmd
            .CommandType = CommandType.Text
            .CommandText = "SELECT " _
                         & "scope_id, " _
                         & "scope_local_id, " _
                         & "scope_sync_knowledge, " _
                         & "scope_tombstone_cleanup_knowledge, " _
                         & "scope_timestamp " _
                         & "FROM Sync.ScopeInfo " _
                         & "WHERE scope_name = @" + DbSyncSession.SyncScopeName
            .Parameters.Add("@" & DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100)
        End With

        sampleDbProvider.SelectScopeInfoCommand = selReplicaInfoCmd


        'Specify the command to update local replica metadata. 
        Dim updReplicaInfoCmd As New SqlCommand()
        With updReplicaInfoCmd
            .CommandType = CommandType.Text
            .CommandText = "UPDATE  Sync.ScopeInfo SET " _
                         & "scope_sync_knowledge = @" + DbSyncSession.SyncScopeKnowledge + ", " _
                         & "scope_id = @" + DbSyncSession.SyncScopeId + ", " _
                         & "scope_tombstone_cleanup_knowledge = @" + DbSyncSession.SyncScopeCleanupKnowledge + " " _
                         & "WHERE scope_name = @" + DbSyncSession.SyncScopeName + " AND " _
                         & " ( @" + DbSyncSession.SyncCheckConcurrency + " = 0 OR scope_timestamp = @" + DbSyncSession.SyncScopeTimestamp + "); " _
                         & "SET @" + DbSyncSession.SyncRowCount + " = @@rowcount"
            .Parameters.Add("@" & DbSyncSession.SyncScopeKnowledge, SqlDbType.VarBinary, 10000)
            .Parameters.Add("@" & DbSyncSession.SyncScopeCleanupKnowledge, SqlDbType.VarBinary, 10000)
            .Parameters.Add("@" & DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100)
            .Parameters.Add("@" & DbSyncSession.SyncCheckConcurrency, SqlDbType.Int)
            .Parameters.Add("@" & DbSyncSession.SyncScopeId, SqlDbType.UniqueIdentifier)
            .Parameters.Add("@" & DbSyncSession.SyncScopeTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" & DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
        End With

        sampleDbProvider.UpdateScopeInfoCommand = updReplicaInfoCmd


        'Return the maximum timestamp from the Customer_Tracking table. 
        'If more tables are synchronized, the query should UNION 
        'all of the results. The table name is not schema-qualified 
        'in this case because the name was not schema qualified in the 
        'DbSyncAdapter constructor. 
        Dim selTableMaxTsCmd As New SqlCommand()
        selTableMaxTsCmd.CommandType = CommandType.Text
        selTableMaxTsCmd.CommandText = "SELECT 'Customer' AS table_name, " _
                                     & "MAX(local_update_peer_timestamp) AS max_timestamp " _
                                     & "FROM Sync.Customer_Tracking"
        sampleDbProvider.SelectTableMaxTimestampsCommand = selTableMaxTsCmd


        'Specify the command to select table and scope names for
        'any tables that are in more than one scope.
        Dim overlappingScopesCmd As New SqlCommand()
        With overlappingScopesCmd
            .CommandType = CommandType.StoredProcedure
            .CommandText = "Sync.sp_SelectSharedScopes"
            .Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100)
        End With

        sampleDbProvider.SelectOverlappingScopesCommand = overlappingScopesCmd

        'Specify the command that updates the scope information table
        'to indicate to which point metadata has been cleaned up for a scope.
        Dim updScopeCleanupInfoCmd As New SqlCommand()
        With updScopeCleanupInfoCmd
            .CommandType = CommandType.Text
            .CommandText = "UPDATE  scope_info set " _
                         & " scope_cleanup_timestamp = @" + DbSyncSession.SyncScopeCleanupTimestamp _
                         & " WHERE scope_name = @" + DbSyncSession.SyncScopeName _
                         & " AND(scope_cleanup_timestamp is null or scope_cleanup_timestamp <  @" + DbSyncSession.SyncScopeCleanupTimestamp + ");" _
                         & " SET @" + DbSyncSession.SyncRowCount + " = @@rowcount"
            .Parameters.Add("@" + DbSyncSession.SyncScopeCleanupTimestamp, SqlDbType.BigInt)
            .Parameters.Add("@" + DbSyncSession.SyncScopeName, SqlDbType.NVarChar, 100)
            .Parameters.Add("@" + DbSyncSession.SyncRowCount, SqlDbType.Int).Direction = ParameterDirection.Output
        End With

        sampleDbProvider.UpdateScopeCleanupTimestampCommand = updScopeCleanupInfoCmd

        Return sampleDbProvider

    End Function
End Class

'Handle the statistics that are returned by the SyncAgent. 
Public Class SampleStats
    Public Sub DisplayStats(ByVal syncStatistics As SyncOperationStatistics, ByVal syncType As String)
        Console.WriteLine([String].Empty)
        If syncType = "initial" Then
            Console.WriteLine("****** Initial Synchronization ******")
        ElseIf syncType = "subsequent" Then
            Console.WriteLine("***** Subsequent Synchronization ****")
        End If

        Console.WriteLine("Start Time: " & syncStatistics.SyncStartTime)
        Console.WriteLine("Total Changes Uploaded: " & syncStatistics.UploadChangesTotal)
        Console.WriteLine("Total Changes Downloaded: " & syncStatistics.DownloadChangesTotal)
        Console.WriteLine("Complete Time: " & syncStatistics.SyncEndTime)
        Console.WriteLine([String].Empty)
    End Sub
End Class

Voir aussi

Autres ressources

Synchronisation d'autre bases de données compatibles ADO.NET