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Como limpar metadados para sincronização de colaboração (não SQL Server)

Dica

Os tópicos desta seção da documentação, Sincronizando outros bancos de dados compatíveis com ADO.NET, foram criados para demonstrar como bancos de dados diferentes do SQL Server podem ser sincronizados usando o Sync Framework. Nesta versão, o SQL Server é usado em exemplos de código, mas o código pode ser usado para outros bancos de dados compatíveis do ADO.NET, com algumas modificações nos objetos específicos do SQL Server (como SqlConnection) e nas consultas SQL mostradas. Para obter informações sobre a sincronização do SQL Server, consulte Como configurar e executar a sincronização de bancos de dados (SQL Server).

Este tópico descreve como limpar metadados do servidor para sincronização de banco de dados ponto a ponto no Sync Framework. O código neste tópico descreve as seguintes classes do Sync Framework:

Para obter informações sobre como executar o código de exemplo, consulte "Exemplo de aplicativos nos tópicos de instruções" em Sincronizando outros bancos de dados compatíveis com ADO.NET.

Noções básicas sobre a limpeza de metadados

A limpeza envolve excluir os metadados das linhas que foram excluídas de uma tabela base. A sincronização ponto a ponto usa dois tipos de metadados:

  • Metadados no nível de tabela que controlam as operações de inserção, atualização e exclusão de cada tabela sincronizada.

    Há uma linha de metadados para cada linha na tabela base. Se uma linha for excluída da tabela base e todos os nós em todos os escopos a receberam, a linha de metadados poderá ser excluída de forma segura.

  • Metadados no nível de banco de dados que controlam quais alterações cada nó recebeu de outros nós.

    Em geral, esses metadados são armazenados em uma única tabela de escopo para cada banco de dados de nó. As linhas da tabela de escopo nunca devem ser excluídas, a menos que o escopo seja descartado.

Para obter mais informações sobre metadados, consulte "Criar tabelas de controle para metadados por tabela" em Como provisionar um banco de dados de servidor para sincronização de colaboração (não SQL Server).

A limpeza de metadados é manipulada pelo aplicativo. Para bancos de dados do SQL Server Compact, use o objeto SqlCeSyncStoreMetadataCleanup:

  • O PerformCleanup é o método que você chama a partir do seu aplicativo.

  • A RetentionInDays é a propriedade que especifica quantos dias os metadados de controle de alterações devem ter para que sejam excluídos quando PerformCleanup é chamado.

Para outros bancos de dados, há três componentes envolvidos na limpeza de metadados:

Diferentemente de outros comandos no objeto DbSyncAdapter, os comandos de limpeza não são chamados de forma automática como parte de cada sessão de sincronização. Eles só são chamados quando um aplicativo chama o método CleanupMetadata. O comando que você especifica para a propriedade SelectMetadataForCleanupCommand pode usar qualquer lógica que seja apropriada ao seu aplicativo, mas, normalmente, baseia-se em retenção: os metadados anteriores a um período de tempo específico são excluídos. Se um nó tentar sincronizar alterações cujos metadados já tenham sido limpos, uma exceção do tipo DbOutdatedSyncException será lançada. O evento SyncPeerOutdated é gerado, fornecendo acesso a um objeto DbOutdatedEventArgs. Há duas opções para tratar esse evento:

  • Defina a propriedade Action como PartialSync. Isso sincroniza os dados nos quais os metadados estão presentes, mas algumas exclusões são perdidas.

  • Defina a propriedade Action como AbortSync (o padrão). Isso encerra a sessão de sincronização. O cliente deve ser reinicializado na próxima sessão de sincronização para que tenha os dados corretos.

Partes Principais da API

O exemplo de código a seguir especifica um comando para a propriedade SelectMetadataForCleanupCommand. O procedimento armazenado que é chamado, sp_Customer_SelectMetadata, assume como parâmetro um período de tempo em horas. Esse é o período de retenção de metadados. Os metadados anteriores a esse período de tempo são removidos. Se você passar um valor igual a -1 ao procedimento, todos os metadados serão removidos, independentemente da idade.

Dica

Este exemplo mostra uma abordagem para a limpeza de metadados. Não é obrigatório que a consulta ou o procedimento use um valor de retenção como um parâmetro ou use -1 para indicar que todos os metadados devem ser limpos.

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

O exemplo de código a seguir cria o procedimento armazenado que é chamado pelo comando de limpeza.

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

O exemplo de código a seguir especifica um comando para a propriedade SelectOverlappingScopesCommand. Este comando e o próximo comando (UpdateScopeCleanupTimestampCommand) permitem que o Sync Framework trate a limpeza de forma adequada quando uma tabela é incluída em mais de um escopo.

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

O exemplo de código a seguir cria o procedimento armazenado que é chamado pelo comando de escopos sobrepostos.

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

O exemplo de código a seguir especifica um comando para a propriedade 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

O exemplo de código a seguir chama o método CleanupMetadata. O código instancia um provedor e chama o método ConfigureDbSyncProvider na classe SampleSyncProvider. Todas as propriedades DbSyncAdapter e DbSyncProvider necessárias são definidas nessa classe. Também está incluída a propriedade SelectMetadataForCleanupCommand. O valor de 7 que é passado ao método ConfigureDbSyncProvider equivale ao período de retenção de metadados em dias.

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

Exemplo de código completo

O exemplo de código completo a seguir inclui os exemplos de código descritos anteriormente e o código adicional para fazer as alterações e sincronizar essas alterações. O código executa as seguintes etapas:

  1. Sincroniza SyncSamplesDb_Peer1 (Node1) e SyncSamplesDb_Peer3 (Node3). Cinco linhas são carregadas no Node3.

  2. Sincroniza Node3 e SyncSampleCe1 (CeNode1).

  3. Atualiza uma linha no Node1.

  4. Chama o CleanupMetadata para metadados que tenham mais de 7 dias no Node1. O método CleanupMetadata retorna com êxito, mas nenhum metadado é limpo, pois nenhuma exclusão com mais de sete dias foi feita no Node1.

  5. Sincroniza o Node1 e o Node3. A sincronização tem êxito porque todos os metadados relevantes ainda estão disponíveis nos dois nós.

  6. Exclui uma linha do Node3.

  7. Chama o CleanupMetadata para todos os metadados no Node3. Os metadados para a exclusão da etapa anterior são limpos.

  8. Sincroniza o Node1 e o Node3. A sincronização falha, pois o conhecimento da sincronização já não corresponde ao estado do nó. Uma exceção do tipo DbOutdatedSyncException é lançada.

É importante remover apenas os metadados que já não são mais necessários aos outros nós. Se a segunda limpeza tivesse ocorrido depois que o Node1 recebeu a exclusão do Node3, a sincronização teria sido bem-sucedida.

Importante

A execução intencional do código de exemplo a seguir deixa os bancos de dados em um estado inconsistente. Depois de executar esse código, descarte os bancos de dados e os recrie executando o script "Controle de alterações personalizado para cenários de colaboração" em Scripts de instalação para tópicos de instruções do provedor de banco de dados.

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

Consulte também

Outros recursos

Sincronizando outros bancos de dados compatíveis com ADO.NET