Compartilhar via


Como usar variáveis de sessão para a sincronização de colaboração

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 colaboração (SQL Server).

Este tópico mostra como usar variáveis de sessão no Sync Framework. Os exemplos deste tópico se concentram nos seguintes tipos e propriedades 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.

Compreendendo as variáveis de sessão

O Sync Framework fornece um conjunto de variáveis de sessão que permitem a passagem de valores para os comandos DbSyncAdapter e DbSyncProvider durante a sincronização. Essas variáveis são especificadas como outros parâmetros para consultas ou procedimentos armazenados em comandos do ADO.NET. Durante uma sessão de sincronização, quando cada objeto de comando ADO.NET é invocado por DbSyncProvider, o provedor passa pela coleção de parâmetros de sincronização (SyncParameters) para determinar se pode fazer a correspondência de cada parâmetro com um parâmetro de comando ADO.NET com base no nome. Se houver uma correspondência com uma variável de sessão interna ou com um parâmetro personalizado que você definiu, a variável será preenchida pelo Sync Framework antes de o provedor chamar o comando.

Por exemplo, a instrução UPDATE a seguir aplica alterações à tabela Customer usando as variáveis de sessão @sync_min_timestamp, @sync_force_write e @sync_row_count.

UPDATE c
SET c.CustomerName = @CustomerName, c.SalesPerson = @SalesPerson, c.CustomerType = @CustomerType      
FROM Sales.Customer c JOIN Sync.Customer_Tracking t ON c.CustomerId = t.CustomerId
WHERE ((t.local_update_peer_timestamp <= @sync_min_timestamp) OR @sync_force_write = 1)
    AND t.CustomerId = @CustomerId  
SET @sync_row_count = @@rowcount

Os valores de @sync_min_timestamp e @sync_force_write são definidos pelo Sync Framework durante a sincronização e o valor de @sync_row_count é definido pela função @@rowcount do SQL Server. Você pode usar os nomes de variáveis diretamente como na consulta anterior ou usar constantes da cadeia de caracteres disponíveis a partir do objeto SyncSession. A tabela a seguir lista todas as variáveis de sessão disponíveis e o seu uso.

Variável de sessão Uso

sync_check_concurrency

Usado pelo Sync Framework para os comandos que atualizam e excluem metadados. O Sync Framework usa este valor para determinar se uma alteração de metadados pode ser feita caso a linha à qual os metadados se referem tenha sido alterada. Se não for possível fazer uma alteração de metadados, o evento ApplyMetadataFailed será gerado.

sync_create_peer_key, sync_create_peer_timestamp, sync_row_is_tombstone, sync_row_timestamp, sync_update_peer_key, sync_update_peer_timestamp, sync_scope_cleanup_timestamp, sync_scope_local_id, sync_shared_scope_name e sync_table_name

Usado pelos comandos que selecionam e aplicam alterações para alterar colunas de controle. Para obter mais informações sobre essas colunas, 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).

sync_force_write

Usado com um ApplyAction de RetryWithForceWrite para impor a aplicação de uma alteração que falhou devido a um conflito ou um erro. Para obter mais informações, consulte Como manipular conflitos de dados e erros de sincronização de colaboração (SQL Server).

sync_initialize

Retorna se a sessão de sincronização atual é a sessão inicial (um valor igual a 1) ou uma sessão subsequente (um valor igual a 0).

sync_metadata_only

Usado pelo Sync Framework para os comandos especificados para as propriedades SelectIncrementalChangesCommand e SelectRowCommand. Quando o Sync Framework especifica um valor igual a 1 para esta variável, ela seleciona somente metadados, mas não as alterações de dados associadas. Essa é uma otimização para casos nos quais o Sync Framework não requer as alterações de dados, como a seleção de linhas conflitantes com o SelectRowCommand.

sync_min_timestamp e sync_new_timestamp

Usado para definir o conjunto de alterações a ser sincronizado durante uma sessão. Durante a sessão de sincronização atual, o comando especificado para a propriedade SelectNewTimestampCommand fornece um novo valor de timestamp. As alterações feitas depois do valor mínimo e antes do novo valor são sincronizadas. O novo valor é armazenado e usado como o valor mínimo durante a próxima sessão de sincronização.

sync_row_count

Retorna o número de linhas afetadas pela última operação no servidor. Nos bancos de dados do SQL Server, @@ROWCOUNT fornece o valor para essa variável. Como mostrado nos exemplos de código neste tópico, os procedimentos armazenados devem incluir um parâmetro de saída que define o valor de sync_row_count.

Uma contagem de linhas igual a 0 indica que uma operação falhou, em geral devido a um conflito ou erro. Para obter mais informações, consulte Como manipular conflitos de dados e erros de sincronização de colaboração (SQL Server).

sync_scope_cleanup_knowledge, sync_scope_id, sync_scope_knowledge, sync_scope_name e sync_scope_timestamp

Usado pelos comandos que selecionam e aplicam alterações à tabela que armazena o conhecimento de sincronização. Para obter um exemplo dessa tabela, consulte "Criar tabelas de controle para metadados por escopo" em Como provisionar um banco de dados de servidor para sincronização de colaboração (não SQL Server).

sync_session_id

Retorna um valor de GUID que identifica a sessão de sincronização atual.

sync_stage_name

Retorna um valor que corresponde a um dos valores na enumeração DbSyncStage.

Exemplo

Os exemplos de código a seguir mostram como usar variáveis de sessão ao sincronizar a tabela Customer no banco de dados par de exemplo do Sync Framework.

Partes principais da API

Esta seção fornece exemplos de código que destacam algumas partes principais da API que abrangem variáveis de sessão. Vários comandos mostrados chamam procedimentos armazenados incluídos no banco de dados par de exemplo. Para obter mais informações, consulte "Criar procedimentos armazenados para selecionar e atualizar dados e metadados" em Como provisionar um banco de dados de servidor para sincronização de colaboração (não SQL Server).

O exemplo de código a seguir especifica uma consulta da propriedade SelectNewTimestampCommand. Essa propriedade define o valor da variável sync_new_timestamp. Esse valor é usado pelos comandos de sincronização que selecionam alterações do banco de dados do servidor.

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;

sampleProvider.SelectNewTimestampCommand = selectNewTimestampCommand;
Dim newTimestampVariable As String = "@" + DbSyncSession.SyncNewTimestamp

Dim selectNewTimestampCommand As New SqlCommand()

With selectNewTimestampCommand
    .CommandText = "SELECT " + newTimestampVariable + " = min_active_rowversion() - 1"
    .Parameters.Add(newTimestampVariable, SqlDbType.Timestamp)
    .Parameters(newTimestampVariable).Direction = ParameterDirection.Output
End With

sampleProvider.SelectNewTimestampCommand = selectNewTimestampCommand

A função MIN_ACTIVE_ROWVERSION retorna o valor ativo mais baixo de timestamp (também conhecido como rowversion) no banco de dados atual. Um valor de timestamp está ativo quando é usado em uma transação ainda não confirmada. Se não houver valores ativos no banco de dados, MIN_ACTIVE_ROWVERSION retornará o mesmo valor que @@DBTS + 1. MIN_ACTIVE_ROWVERSION é útil para cenários, como sincronização de dados, que usam valores timestamp para agrupar conjuntos de alterações. Se um aplicativo usar @@DBTS em seus comandos de âncora em vez de MIN_ACTIVE_ROWVERSION, ele poderá perder alterações ativas quando ocorrer a sincronização.

O exemplo de código a seguir especifica um procedimento armazenado SelectIncrementalChangesCommand para a propriedade. O procedimento seleciona inserções, atualizações e exclusões de um par para aplicar a um segundo par durante a sessão de sincronização. A variável sync_min_timestamp especifica o timestamp mínimo incluído no conjunto de alterações a ser sincronizado. O valor dessa variável é comparado aos valores na coluna sync_row_timestamp na tabela de rastreamento para determinar quais linhas devem ser selecionadas. A variável sync_initialize é usada para especificar se uma sessão de sincronização é a primeira sessão entre dois pares. Se essa for a primeira sessão entre dois pares, o procedimento armazenado sp_Customer_SelectChanges poderá incluir lógica que executa somente durante a primeira sessão.

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;
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

O exemplo de código a seguir especifica um comando para aplicar as atualizações a um par selecionado de outro par. A variável sync_row_count permite que o Sync Framework determine se uma atualização teve êxito ou falhou. Se uma atualização falhar, a variável sync_force_write poderá ser definida como igual a 1. Isso permite lógica diferente no procedimento armazenado sp_Customer_ApplyUpdate. Para obter mais informações, consulte Como manipular conflitos de dados e erros de sincronização de colaboração (SQL Server). Antes de uma atualização ser aplicada em um par, a variável sync_min_timestamp é usada para verificar se uma linha foi atualizada no par desde a sessão de sincronização anterior.

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;
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

Os exemplos de código a seguir especificam os comandos que aplicam atualizações às tabelas Customer_Tracking e ScopeInfo. A maioria das variáveis de sessão corresponde a colunas nas tabelas de rastreamento. A variável sync_check_concurrency é usada nos comandos para determinar se alterações de metadados podem ser feitas quando as linhas às quais os metadados se referem foram alteradas.

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;
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
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;

sampleProvider.UpdateScopeInfoCommand = updReplicaInfoCmd;
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

sampleProvider.UpdateScopeInfoCommand = updReplicaInfoCmd

Exemplo de código completo

O exemplo de código completo a seguir inclui os exemplos de código descritos anteriormente neste tópico e código adicional para executar a sincronização. O exemplo requer a classe Utility disponível em Classe de utilitário para tópicos de instruções do provedor de banco de dados.

using System;
using System.IO;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using Microsoft.Synchronization;
using Microsoft.Synchronization.Data;

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

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

            try
            {
                //Initial synchronization. Instantiate the SyncOrchestrator
                //and call Synchronize. Note that data is not synchronized during the
                //session between peer 1 and peer 3, because all rows have already
                //been delivered to peer 3 during its synchronization session with peer 2.
                SyncOrchestrator sampleSyncAgent;
                SyncOperationStatistics syncStatistics;

                sampleSyncAgent = new SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2);
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "initial");

                sampleSyncAgent = new SampleSyncAgent(Utility.ConnStr_DbSync2, Utility.ConnStr_DbSync3);
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "initial");

                sampleSyncAgent = new SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync3);
                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);
            }

            //Make changes in each peer database.
            Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync1, "Customer");
            Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync2, "Customer");
            Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync3, "Customer");

            try
            {
                //Subsequent synchronization. Changes are now synchronized between all
                //peers.
                SyncOrchestrator sampleSyncAgent;
                SyncOperationStatistics syncStatistics;

                sampleSyncAgent = new SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2);
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "subsequent");

                sampleSyncAgent = new SampleSyncAgent(Utility.ConnStr_DbSync2, Utility.ConnStr_DbSync3);
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "subsequent");

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

                //Sessions in which no new changes have been made.
                //In this case, the call to SelectTableMaxTimestampsCommand indicates 
                //that no data changes are available to synchronize, so
                //SelectIncrementalChangesCommand is not called.
                sampleSyncAgent = new SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2);
                syncStatistics = sampleSyncAgent.Synchronize();
                sampleStats.DisplayStats(syncStatistics, "subsequent");

                sampleSyncAgent = new SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2);
                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);
            }

            //Return peer data back to its original state.
            Utility.CleanUpNode(Utility.ConnStr_DbSync1);
            Utility.CleanUpNode(Utility.ConnStr_DbSync2);
            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(string localProviderConnString, string remoteProviderConnString)
            {

                //Instantiate the sample provider that allows us to create a provider
                //for both of the peers that are being synchronized.
                SampleSyncProvider sampleSyncProvider = new SampleSyncProvider();

                //Instantiate a DbSyncProvider for the local peer and the remote peer.
                //For example, if this code is running at peer1 and is
                //synchronizing with peer2, peer1 would be the local provider
                //and peer2 the remote provider.
                DbSyncProvider localProvider = new DbSyncProvider();
                DbSyncProvider remoteProvider = new DbSyncProvider();

                //Create a provider by using the SetupSyncProvider on the sample class.             
                sampleSyncProvider.SetupSyncProvider(localProviderConnString, localProvider);
                localProvider.SyncProviderPosition = SyncProviderPosition.Local;
                
                sampleSyncProvider.SetupSyncProvider(remoteProviderConnString, remoteProvider);
                remoteProvider.SyncProviderPosition = SyncProviderPosition.Remote;

                //Specify the local and remote providers that should be synchronized,
                //and the direction and order of changes. In this case, changes are first
                //uploaded from remote to local and then downloaded in the other direction.
                this.LocalProvider = localProvider;
                this.RemoteProvider = remoteProvider;
                this.Direction = SyncDirectionOrder.UploadAndDownload;
            }
        }


        public class SampleSyncProvider
        {
            public DbSyncProvider SetupSyncProvider(string peerConnString, DbSyncProvider sampleProvider)
            {

                SqlConnection peerConnection = new SqlConnection(peerConnString);
                sampleProvider.Connection = peerConnection;
                sampleProvider.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;


                //Add the adapter to the provider.
                sampleProvider.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.
                // There are additional commands related to metadata cleanup that are not 
                // included in this application.


                //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;
                
                sampleProvider.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);
                
                sampleProvider.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;
                
                sampleProvider.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";
                sampleProvider.SelectTableMaxTimestampsCommand = selTableMaxTsCmd;

                return sampleProvider;
            }
        }

        //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.Text
Imports System.Data
Imports System.Data.SqlClient
Imports Microsoft.Synchronization
Imports Microsoft.Synchronization.Data

Class Program

    Shared Sub Main(ByVal args() As String)

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

        Try
            'Initial synchronization. Instantiate the SyncOrchestrator
            'and call Synchronize. Note that data is not synchronized during the
            'session between peer 1 and peer 3, because all rows have already
            'been delivered to peer 3 during its synchronization session with peer 2.              
            Dim sampleSyncAgent As SyncOrchestrator
            Dim syncStatistics As SyncOperationStatistics

            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2)
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "initial")

            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync2, Utility.ConnStr_DbSync3)
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "initial")

            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync3)
            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

        'Make changes in each peer database.
        Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync1, "Customer")
        Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync2, "Customer")
        Utility.MakeDataChangesOnNode(Utility.ConnStr_DbSync3, "Customer")

        Try
            'Subsequent synchronization. Changes are now synchronized between all
            'peers.
            Dim sampleSyncAgent As SyncOrchestrator
            Dim syncStatistics As SyncOperationStatistics

            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2)
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "subsequent")

            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync2, Utility.ConnStr_DbSync3)
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "subsequent")

            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync3)
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "subsequent")

            'Sessions in which no new changes have been made.
            'In this case, the call to SelectTableMaxTimestampsCommand indicates 
            'that no data changes are available to synchronize, so
            'SelectIncrementalChangesCommand is not called.
            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2)
            syncStatistics = sampleSyncAgent.Synchronize()
            sampleStats.DisplayStats(syncStatistics, "subsequent")

            sampleSyncAgent = New SampleSyncAgent(Utility.ConnStr_DbSync1, Utility.ConnStr_DbSync2)
            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

        'Return peer data back to its original state.
        Utility.CleanUpNode(Utility.ConnStr_DbSync1)
        Utility.CleanUpNode(Utility.ConnStr_DbSync2)
        Utility.CleanUpNode(Utility.ConnStr_DbSync3)

        'Exit.
        Console.Write(vbLf + "Press Enter to close the window.")
        Console.ReadLine()

    End Sub 'Main

End Class 'Program

'Create a class that is derived from 
'Microsoft.Synchronization.SyncOrchestrator.
Public Class SampleSyncAgent
    Inherits SyncOrchestrator

    Public Sub New(ByVal localProviderConnString As String, ByVal remoteProviderConnString As String)

        'Instantiate the sample provider that allows us to create a provider
        'for both of the peers that are being synchronized.
        Dim sampleSyncProvider As New SampleSyncProvider()

        'Instantiate a DbSyncProvider for the local peer and the remote peer.
        'For example, if this code is running at peer1 and is
        'synchronizing with peer2, peer1 would be the local provider
        'and peer2 the remote provider.  
        Dim localProvider As New DbSyncProvider()
        Dim remoteProvider As New DbSyncProvider()

        'Create a provider by using the SetupSyncProvider on the sample class.
        sampleSyncProvider.SetupSyncProvider(localProviderConnString, localProvider)
        localProvider.SyncProviderPosition = SyncProviderPosition.Local

        sampleSyncProvider.SetupSyncProvider(remoteProviderConnString, remoteProvider)
        remoteProvider.SyncProviderPosition = SyncProviderPosition.Remote

        'Specify the local and remote providers that should be synchronized,
        'and the direction and order of changes. In this case, changes are first
        'uploaded from local to remote and then downloaded in the other direction.
        Me.LocalProvider = localProvider
        Me.RemoteProvider = remoteProvider
        Me.Direction = SyncDirectionOrder.UploadAndDownload

    End Sub 'New
End Class 'SampleSyncAgent

Public Class SampleSyncProvider

    Public Function SetupSyncProvider(ByVal peerConnString As String, ByVal sampleProvider As DbSyncProvider) As DbSyncProvider

        Dim peerConnection As New SqlConnection(peerConnString)
        sampleProvider.Connection = peerConnection
        sampleProvider.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. These are the same columns
        'that were specified as DbSyncAdapter properties at the beginning 
        'of this code example.
        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


        sampleProvider.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.
        ' There are additional commands related to metadata cleanup that are not 
        ' included in this application.           


        '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 newTimestampVariable As String = "@" + DbSyncSession.SyncNewTimestamp

        Dim selectNewTimestampCommand As New SqlCommand()

        With selectNewTimestampCommand
            .CommandText = "SELECT " + newTimestampVariable + " = min_active_rowversion() - 1"
            .Parameters.Add(newTimestampVariable, SqlDbType.Timestamp)
            .Parameters(newTimestampVariable).Direction = ParameterDirection.Output
        End With

        sampleProvider.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

        sampleProvider.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

        sampleProvider.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"
        sampleProvider.SelectTableMaxTimestampsCommand = selTableMaxTsCmd

        Return sampleProvider

    End Function 'SetupSyncProvider

End Class 'SampleSyncProvider


'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 'DisplayStats
End Class 'SampleStats

Consulte também

Conceitos

Sincronizando outros bancos de dados compatíveis com ADO.NET