如何指定变更的顺序和批大小

本主题介绍如何为通过使用 Sync Framework 下载到客户端数据库的变更指定顺序和批大小。本主题中的示例着重介绍以下 Sync Framework 类型和事件:

有关如何运行示例代码的信息,请参见对常见客户端与服务器同步任务进行编程中的“帮助主题中的示例应用程序”。

了解同步顺序和批处理

对于每个进行同步的表,按插入、更新和删除的顺序从服务器数据库中选择变更。按删除、插入和更新的顺序将变更应用于客户端数据库。当对多个表进行同步时,每个表中的处理顺序取决于将其 SyncTable 对象添加到同步代理的表集合时的顺序。例如,如果 CustomerOrderHeader 表以该顺序添加,则先选择 Customer 表的插入,再选择更新和删除。然后选择对 OrderHeader 表所做的变更。所有 Customer 表的变更将在一个事务中应用到客户端数据库(如果未使用批处理),然后在另一个事务中应用 OrderHeader 的变更。如果将 CustomerOrderHeader 表分配给同一 SyncGroup 对象,则会一起选择这两个表的插入、更新和删除。所有变更将在一个事务中应用到客户端数据库(同样,如果未使用批处理)。

默认情况下,Sync Framework 不将变更分批处理。变更将作为一个单元下载到客户端数据库或从客户端数据库上载。对于许多应用程序,可将变更分成较小的批处理。例如,如果同步会话中断,则可以从上一批处理重新开始同步,无需重新发送所有变更。性能方面也会有好处,因为客户端可以同时管理一批更少的变更。由于这些优点,Sync Framework 使应用程序能够将多批变更下载到客户端(上载不支持批处理)。

通过为 BatchSize 属性指定一个值,并为 SelectNewAnchorCommand 属性创建一个可返回每批变更的定位点值的命令,可以启用批处理。如果不使用批处理,应用程序将使用新定位点和上一个定位点值来定义要下载的整个变更集的上下限。有关更多信息,请参见入门:客户端与服务器同步。使用批处理时,收到的最大定位点值定义整个变更集的上限,新定位点值和上一个定位点值定义每批变更的上下限。SessionProgress 事件为监视整体同步进度提供了一种便捷的途径,BatchProgress 属性在批处理级别上提供对进度信息的访问。

示例

下面的代码示例演示如何同步 Sync Framework 示例数据库中的 Customer OrderHeader 表。这些表的变更分批下载,每批 50 个变更。初始同步下载 10 行。所有行都在一批中下载并在一个事务中应用。后续同步分两批下载 92 行。每个批次都包含 Customer 表和 OrderHeader 表中的变更,每个批次都在一个事务中应用。

API 的要点

本节提供的代码示例指出了在对变更进行排序和批处理时要使用的 API 的要点。下面的代码示例摘自从 SyncAgent 派生的类。代码为 CustomerOrderHeader 表创建一个 SyncGroup 对象。

//Create a SyncGroup so that changes to Customer
//and OrderHeader are made in one transaction.
SyncGroup customerOrderSyncGroup = new SyncGroup("CustomerOrder");

//Add each table: specify a synchronization direction of
//DownloadOnly.
SyncTable customerSyncTable = new SyncTable("Customer");
customerSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable;
customerSyncTable.SyncDirection = SyncDirection.DownloadOnly;
customerSyncTable.SyncGroup = customerOrderSyncGroup;
this.Configuration.SyncTables.Add(customerSyncTable);

SyncTable orderHeaderSyncTable = new SyncTable("OrderHeader");
orderHeaderSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable;
orderHeaderSyncTable.SyncDirection = SyncDirection.DownloadOnly;
orderHeaderSyncTable.SyncGroup = customerOrderSyncGroup;
this.Configuration.SyncTables.Add(orderHeaderSyncTable);
'Create a SyncGroup so that changes to Customer
'and OrderHeader are made in one transaction.
Dim customerOrderSyncGroup As New SyncGroup("CustomerOrder")

'Add each table: specify a synchronization direction of
'DownloadOnly.
Dim customerSyncTable As New SyncTable("Customer")
customerSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable
customerSyncTable.SyncDirection = SyncDirection.DownloadOnly
customerSyncTable.SyncGroup = customerOrderSyncGroup
Me.Configuration.SyncTables.Add(customerSyncTable)

Dim orderHeaderSyncTable As New SyncTable("OrderHeader")
orderHeaderSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable
orderHeaderSyncTable.SyncDirection = SyncDirection.DownloadOnly
orderHeaderSyncTable.SyncGroup = customerOrderSyncGroup
Me.Configuration.SyncTables.Add(orderHeaderSyncTable)

下面的代码示例摘自从 DbServerSyncProvider 派生的类。代码为不使用批处理的应用程序创建一个定位点命令。该命令为要同步的整个变更集一次返回一个新定位点值。使用本示例的目的是为了可以更容易地区分使用批处理的命令和不使用批处理的命令。

SqlCommand selectNewAnchorCommand = new SqlCommand();
string newAnchorVariable = "@" + SyncSession.SyncNewReceivedAnchor;
selectNewAnchorCommand.CommandText = "SELECT " + newAnchorVariable + " = min_active_rowversion() - 1";
selectNewAnchorCommand.Parameters.Add(newAnchorVariable, SqlDbType.Timestamp);
selectNewAnchorCommand.Parameters[newAnchorVariable].Direction = ParameterDirection.Output;
selectNewAnchorCommand.Connection = serverConn;
this.SelectNewAnchorCommand = selectNewAnchorCommand;
Dim selectNewAnchorCommand As New SqlCommand()
Dim newAnchorVariable As String = "@" + SyncSession.SyncNewReceivedAnchor
selectNewAnchorCommand.CommandText = "SELECT " + newAnchorVariable + " = min_active_rowversion() - 1"
selectNewAnchorCommand.Parameters.Add(newAnchorVariable, SqlDbType.Timestamp)
selectNewAnchorCommand.Parameters(newAnchorVariable).Direction = ParameterDirection.Output
selectNewAnchorCommand.Connection = serverConn
Me.SelectNewAnchorCommand = selectNewAnchorCommand

下面的代码示例创建一个定位点命令,如果分批发送变更,则可以使用该命令。该命令为每批变更返回一个新定位点值,而不是为整个变更集返回一个新定位点值。示例使用 BatchSize 属性指定每批中的变更数,并指定用于在存储过程和同步运行时之间来回传递定位点值的会话变量。手动编写同步适配器命令时,仍可以使用 @sync_new_received_anchor@sync_last_received_anchor 会话变量;@sync_max_received_anchor 会话变量仅供新定位点命令使用。

SqlCommand selectNewAnchorCommand = new SqlCommand();
selectNewAnchorCommand.Connection = serverConn;
selectNewAnchorCommand.CommandText = "usp_GetNewBatchAnchor";
selectNewAnchorCommand.CommandType = CommandType.StoredProcedure;            
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp, 8);
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncMaxReceivedAnchor, SqlDbType.Timestamp, 8);
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp, 8);
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchSize, SqlDbType.Int, 4);
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchCount, SqlDbType.Int, 4);            

selectNewAnchorCommand.Parameters["@" + SyncSession.SyncMaxReceivedAnchor].Direction = ParameterDirection.Output;
selectNewAnchorCommand.Parameters["@" + SyncSession.SyncNewReceivedAnchor].Direction = ParameterDirection.Output;
selectNewAnchorCommand.Parameters["@" + SyncSession.SyncBatchCount].Direction = ParameterDirection.InputOutput;
this.SelectNewAnchorCommand = selectNewAnchorCommand;
this.BatchSize = 50;
Dim selectNewAnchorCommand As New SqlCommand()
selectNewAnchorCommand.Connection = serverConn
selectNewAnchorCommand.CommandText = "usp_GetNewBatchAnchor"
selectNewAnchorCommand.CommandType = CommandType.StoredProcedure
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp, 8)
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncMaxReceivedAnchor, SqlDbType.Timestamp, 8)
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp, 8)
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchSize, SqlDbType.Int, 4)
selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchCount, SqlDbType.Int, 4)

selectNewAnchorCommand.Parameters("@" + SyncSession.SyncMaxReceivedAnchor).Direction = ParameterDirection.Output
selectNewAnchorCommand.Parameters("@" + SyncSession.SyncNewReceivedAnchor).Direction = ParameterDirection.Output
selectNewAnchorCommand.Parameters("@" + SyncSession.SyncBatchCount).Direction = ParameterDirection.InputOutput
Me.SelectNewAnchorCommand = selectNewAnchorCommand
Me.BatchSize = 50

下面的代码示例创建一个存储过程,该存储过程输出新定位点值、一个最大定位点值以及插入和更新的当前批处理计数。该过程使服务器同步提供程序可以从服务器数据库中选择变更批次。此存储过程中的逻辑只是一个示例,您可以使用能提供此处所示的输出值的任何逻辑。该示例代码的缺点之一是,如果某行在同步之间变更超过 50 次,则会出现空批处理。可以添加逻辑来处理这种情况。

CREATE PROCEDURE usp_GetNewBatchAnchor (
    @sync_last_received_anchor timestamp, 
    @sync_batch_size bigint,
    @sync_max_received_anchor timestamp out,
    @sync_new_received_anchor timestamp out,            
    @sync_batch_count int output)            
AS            
       -- Set a default batch size if a valid one is not passed in.
       IF  @sync_batch_size IS NULL OR @sync_batch_size <= 0
         SET @sync_batch_size = 1000    

       -- Before selecting the first batch of changes,
       -- set the maximum anchor value for this synchronization session.
       -- After the first time that this procedure is called, 
       -- Sync Framework passes a value for @sync_max_received_anchor
       -- to the procedure. Batches of changes are synchronized until this 
       -- value is reached.
       IF @sync_max_received_anchor IS NULL
         SELECT  @sync_max_received_anchor = MIN_ACTIVE_ROWVERSION() - 1
       
       -- If this is the first synchronization session for a database,
       -- get the lowest timestamp value from the tables. By default,
       -- Sync Framework uses a value of 0 for @sync_last_received_anchor
       -- on the first synchronization. If you do not set @sync_last_received_anchor,
       -- this can cause empty batches to be downloaded until the lowest
       -- timestamp value is reached.
       IF @sync_last_received_anchor IS NULL OR @sync_last_received_anchor = 0
       BEGIN
                
        SELECT @sync_last_received_anchor = MIN(TimestampCol) FROM (
          SELECT MIN(UpdateTimestamp) AS TimestampCol FROM Sales.Customer
          UNION
          SELECT MIN(InsertTimestamp) AS TimestampCol FROM Sales.Customer
          UNION
          SELECT MIN(UpdateTimestamp) AS TimestampCol FROM Sales.OrderHeader
          UNION
          SELECT MIN(InsertTimestamp) AS TimestampCol FROM Sales.OrderHeader
        ) MinTimestamp  
       
        SET @sync_new_received_anchor = @sync_last_received_anchor + @sync_batch_size

        -- Determine how many batches are required during the initial synchronization.
        IF @sync_batch_count <= 0
          SET @sync_batch_count = ((@sync_max_received_anchor / @sync_batch_size) - (@sync_last_received_anchor /  @sync_batch_size))

        END

       ELSE
       BEGIN

        SET @sync_new_received_anchor = @sync_last_received_anchor + @sync_batch_size

        -- Determine how many batches are required during subsequent synchronizations.
        IF @sync_batch_count <= 0
          SET @sync_batch_count = ((@sync_max_received_anchor / @sync_batch_size) - (@sync_new_received_anchor /  @sync_batch_size)) + 1  
       
       END

       -- Check whether this is the last batch.      
       IF @sync_new_received_anchor >= @sync_max_received_anchor
       BEGIN

         SET @sync_new_received_anchor = @sync_max_received_anchor        
         IF @sync_batch_count <= 0
           SET @sync_batch_count = 1

       END
GO

完整的代码示例

下面的完整代码示例包括了上面介绍的代码示例以及用于执行同步的其他代码。示例需要 Utility 类,可通过用于数据库提供程序帮助主题的 Utility 类获得该类。

using System;
using System.IO;
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.Server;
using Microsoft.Synchronization.Data.SqlServerCe;

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 and
            //from SyncAgent events.
            SampleStats sampleStats = new SampleStats();

            //Request a password for the client database, and delete
            //and re-create the database. The client synchronization
            //provider also enables you to create the client database 
            //if it does not exist.
            Utility.SetPassword_SqlCeClientSync();
            Utility.DeleteAndRecreateCompactDatabase(Utility.ConnStr_SqlCeClientSync, true);
            
            //Initial synchronization. Instantiate the SyncAgent
            //and call Synchronize.
            SampleSyncAgent sampleSyncAgent = new SampleSyncAgent();
            SyncStatistics syncStatistics = sampleSyncAgent.Synchronize();
            sampleStats.DisplayStats(syncStatistics, "initial");

            //Make changes on the server.
            Utility.MakeDataChangesOnServer("CustomerAndOrderHeader");

            //Subsequent synchronization.
            syncStatistics = sampleSyncAgent.Synchronize();
            sampleStats.DisplayStats(syncStatistics, "subsequent");

            //Return server data back to its original state.
            Utility.CleanUpServer();

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

    //Create a class that is derived from 
    //Microsoft.Synchronization.SyncAgent.
    public class SampleSyncAgent : SyncAgent
    {
        public SampleSyncAgent()
        {
            //Instantiate a client synchronization provider and specify it
            //as the local provider for this synchronization agent.
            this.LocalProvider = new SampleClientSyncProvider();

            //Instantiate a server synchronization provider and specify it
            //as the remote provider for this synchronization agent.
            this.RemoteProvider = new SampleServerSyncProvider();

            //Create a SyncGroup so that changes to Customer
            //and OrderHeader are made in one transaction.
            SyncGroup customerOrderSyncGroup = new SyncGroup("CustomerOrder");

            //Add each table: specify a synchronization direction of
            //DownloadOnly.
            SyncTable customerSyncTable = new SyncTable("Customer");
            customerSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable;
            customerSyncTable.SyncDirection = SyncDirection.DownloadOnly;
            customerSyncTable.SyncGroup = customerOrderSyncGroup;
            this.Configuration.SyncTables.Add(customerSyncTable);

            SyncTable orderHeaderSyncTable = new SyncTable("OrderHeader");
            orderHeaderSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable;
            orderHeaderSyncTable.SyncDirection = SyncDirection.DownloadOnly;
            orderHeaderSyncTable.SyncGroup = customerOrderSyncGroup;
            this.Configuration.SyncTables.Add(orderHeaderSyncTable);
        }
    }

    //Create a class that is derived from 
    //Microsoft.Synchronization.Server.DbServerSyncProvider.
    public class SampleServerSyncProvider : DbServerSyncProvider
    {
        public SampleServerSyncProvider()
        {
            //Create a connection to the sample server database.
            Utility util = new Utility();
            SqlConnection serverConn = new SqlConnection(Utility.ConnStr_DbServerSync);
            this.Connection = serverConn;

            //Create a command to retrieve a new anchor value from
            //the server. In this case, we call a stored procedure
            //that returns an anchor that can be used with batches
            //of changes.
            SqlCommand selectNewAnchorCommand = new SqlCommand();
            selectNewAnchorCommand.Connection = serverConn;
            selectNewAnchorCommand.CommandText = "usp_GetNewBatchAnchor";
            selectNewAnchorCommand.CommandType = CommandType.StoredProcedure;            
            selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp, 8);
            selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncMaxReceivedAnchor, SqlDbType.Timestamp, 8);
            selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp, 8);
            selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchSize, SqlDbType.Int, 4);
            selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchCount, SqlDbType.Int, 4);            

            selectNewAnchorCommand.Parameters["@" + SyncSession.SyncMaxReceivedAnchor].Direction = ParameterDirection.Output;
            selectNewAnchorCommand.Parameters["@" + SyncSession.SyncNewReceivedAnchor].Direction = ParameterDirection.Output;
            selectNewAnchorCommand.Parameters["@" + SyncSession.SyncBatchCount].Direction = ParameterDirection.InputOutput;
            this.SelectNewAnchorCommand = selectNewAnchorCommand;
            this.BatchSize = 50;
            
            //Create SyncAdapters for each table by using the SqlSyncAdapterBuilder:
            //  * Specify the base table and tombstone table names.
            //  * Specify the columns that are used to track when
            //    and where changes are made.
            //  * Specify download only synchronization.
            //  * Call ToSyncAdapter to create the SyncAdapter.
            //  * Specify a name for the SyncAdapter that matches the
            //    the name specified for the corresponding SyncTable.
            //    Do not include the schema names (Sales in this case).

            //Customer table
            SqlSyncAdapterBuilder customerBuilder = new SqlSyncAdapterBuilder(serverConn);

            customerBuilder.TableName = "Sales.Customer";
            customerBuilder.TombstoneTableName = customerBuilder.TableName + "_Tombstone";
            customerBuilder.SyncDirection = SyncDirection.DownloadOnly;
            customerBuilder.CreationTrackingColumn = "InsertTimestamp";
            customerBuilder.UpdateTrackingColumn = "UpdateTimestamp";
            customerBuilder.DeletionTrackingColumn = "DeleteTimestamp";
            
            SyncAdapter customerSyncAdapter = customerBuilder.ToSyncAdapter();
            customerSyncAdapter.TableName = "Customer";
            this.SyncAdapters.Add(customerSyncAdapter);


            //OrderHeader table.
            SqlSyncAdapterBuilder orderHeaderBuilder = new SqlSyncAdapterBuilder(serverConn);

            orderHeaderBuilder.TableName = "Sales.OrderHeader";
            orderHeaderBuilder.TombstoneTableName = orderHeaderBuilder.TableName + "_Tombstone";
            orderHeaderBuilder.SyncDirection = SyncDirection.DownloadOnly;
            orderHeaderBuilder.CreationTrackingColumn = "InsertTimestamp";
            orderHeaderBuilder.UpdateTrackingColumn = "UpdateTimestamp";
            orderHeaderBuilder.DeletionTrackingColumn = "DeleteTimestamp";

            SyncAdapter orderHeaderSyncAdapter = orderHeaderBuilder.ToSyncAdapter();
            orderHeaderSyncAdapter.TableName = "OrderHeader";
            this.SyncAdapters.Add(orderHeaderSyncAdapter);

            //Handle the ChangesSelected event, and display
            //information to the console.
            this.ChangesSelected += new EventHandler<ChangesSelectedEventArgs>(SampleServerSyncProvider_ChangesSelected);
        }

        public void SampleServerSyncProvider_ChangesSelected(object sender, ChangesSelectedEventArgs e)
        {
            Console.WriteLine("Total number of batches: " + e.Context.BatchCount);
            Console.WriteLine("Changes applied for group " + e.GroupMetadata.GroupName);
            Console.WriteLine("Inserts applied for group: " + e.Context.GroupProgress.TotalInserts.ToString());
            Console.WriteLine("Updates applied for group: " + e.Context.GroupProgress.TotalUpdates.ToString());
            Console.WriteLine("Deletes applied for group: " + e.Context.GroupProgress.TotalDeletes.ToString());
        }
    }

    //Create a class that is derived from 
    //Microsoft.Synchronization.Data.SqlServerCe.SqlCeClientSyncProvider.
    public class SampleClientSyncProvider : SqlCeClientSyncProvider
    {

        public SampleClientSyncProvider()
        {
            //Specify a connection string for the sample client database.
            Utility util = new Utility();
            this.ConnectionString = Utility.ConnStr_SqlCeClientSync;         
        }
    }

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

            Console.WriteLine("Start Time: " + syncStatistics.SyncStartTime);
            Console.WriteLine("Total Changes Downloaded: " + syncStatistics.TotalChangesDownloaded);
            Console.WriteLine("Complete Time: " + syncStatistics.SyncCompleteTime);
            Console.WriteLine(String.Empty);
        }
    }         
}
Imports System
Imports System.IO
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.Server
Imports Microsoft.Synchronization.Data.SqlServerCe

Class Program

    Shared Sub Main(ByVal args() As String)

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

        'Request a password for the client database, and delete
        'and re-create the database. The client synchronization
        'provider also enables you to create the client database 
        'if it does not exist.
        Utility.SetPassword_SqlCeClientSync()
        Utility.DeleteAndRecreateCompactDatabase(Utility.ConnStr_SqlCeClientSync, True)

        'Initial synchronization. Instantiate the SyncAgent
        'and call Synchronize.
        Dim sampleSyncAgent As New SampleSyncAgent()
        Dim syncStatistics As SyncStatistics = sampleSyncAgent.Synchronize()
        sampleStats.DisplayStats(syncStatistics, "initial")

        'Make changes on the server.
        Utility.MakeDataChangesOnServer("CustomerAndOrderHeader")

        'Subsequent synchronization.
        syncStatistics = sampleSyncAgent.Synchronize()
        sampleStats.DisplayStats(syncStatistics, "subsequent")

        'Return server data back to its original state.
        Utility.CleanUpServer()

        '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.SyncAgent.

Public Class SampleSyncAgent
    Inherits SyncAgent

    Public Sub New()
        'Instantiate a client synchronization provider and specify it
        'as the local provider for this synchronization agent.
        Me.LocalProvider = New SampleClientSyncProvider()

        'Instantiate a server synchronization provider and specify it
        'as the remote provider for this synchronization agent.
        Me.RemoteProvider = New SampleServerSyncProvider()

        'Create a SyncGroup so that changes to Customer
        'and OrderHeader are made in one transaction.
        Dim customerOrderSyncGroup As New SyncGroup("CustomerOrder")

        'Add each table: specify a synchronization direction of
        'DownloadOnly.
        Dim customerSyncTable As New SyncTable("Customer")
        customerSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable
        customerSyncTable.SyncDirection = SyncDirection.DownloadOnly
        customerSyncTable.SyncGroup = customerOrderSyncGroup
        Me.Configuration.SyncTables.Add(customerSyncTable)

        Dim orderHeaderSyncTable As New SyncTable("OrderHeader")
        orderHeaderSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable
        orderHeaderSyncTable.SyncDirection = SyncDirection.DownloadOnly
        orderHeaderSyncTable.SyncGroup = customerOrderSyncGroup
        Me.Configuration.SyncTables.Add(orderHeaderSyncTable)

End Class 'SampleSyncAgent

'Create a class that is derived from 
'Microsoft.Synchronization.Server.DbServerSyncProvider.

Public Class SampleServerSyncProvider
    Inherits DbServerSyncProvider

    Public Sub New()
        'Create a connection to the sample server database.
        Dim util As New Utility()
        Dim serverConn As New SqlConnection(Utility.ConnStr_DbServerSync)
        Me.Connection = serverConn

        'Create a command to retrieve a new anchor value from
        'the server. In this case, we call a stored procedure
        'that returns an anchor that can be used with batches
        'of changes.
        Dim selectNewAnchorCommand As New SqlCommand()
        selectNewAnchorCommand.Connection = serverConn
        selectNewAnchorCommand.CommandText = "usp_GetNewBatchAnchor"
        selectNewAnchorCommand.CommandType = CommandType.StoredProcedure
        selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp, 8)
        selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncMaxReceivedAnchor, SqlDbType.Timestamp, 8)
        selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp, 8)
        selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchSize, SqlDbType.Int, 4)
        selectNewAnchorCommand.Parameters.Add("@" + SyncSession.SyncBatchCount, SqlDbType.Int, 4)

        selectNewAnchorCommand.Parameters("@" + SyncSession.SyncMaxReceivedAnchor).Direction = ParameterDirection.Output
        selectNewAnchorCommand.Parameters("@" + SyncSession.SyncNewReceivedAnchor).Direction = ParameterDirection.Output
        selectNewAnchorCommand.Parameters("@" + SyncSession.SyncBatchCount).Direction = ParameterDirection.InputOutput
        Me.SelectNewAnchorCommand = selectNewAnchorCommand
        Me.BatchSize = 50
        'Create SyncAdapters for each table by using the SqlSyncAdapterBuilder:
        '  * Specify the base table and tombstone table names.
        '  * Specify the columns that are used to track when
        '    and where changes are made.
        '  * Specify download only synchronization.
        '  * Call ToSyncAdapter to create the SyncAdapter.
        '  * Specify a name for the SyncAdapter that matches the
        '    the name specified for the corresponding SyncTable.
        '    Do not include the schema names (Sales in this case).
        'Customer table
        Dim customerBuilder As New SqlSyncAdapterBuilder(serverConn)

        customerBuilder.TableName = "Sales.Customer"
        customerBuilder.TombstoneTableName = customerBuilder.TableName + "_Tombstone"
        customerBuilder.SyncDirection = SyncDirection.DownloadOnly
        customerBuilder.CreationTrackingColumn = "InsertTimestamp"
        customerBuilder.UpdateTrackingColumn = "UpdateTimestamp"
        customerBuilder.DeletionTrackingColumn = "DeleteTimestamp"

        Dim customerSyncAdapter As SyncAdapter = customerBuilder.ToSyncAdapter()
        customerSyncAdapter.TableName = "Customer"
        Me.SyncAdapters.Add(customerSyncAdapter)


        'OrderHeader table.
        Dim orderHeaderBuilder As New SqlSyncAdapterBuilder(serverConn)

        orderHeaderBuilder.TableName = "Sales.OrderHeader"
        orderHeaderBuilder.TombstoneTableName = orderHeaderBuilder.TableName + "_Tombstone"
        orderHeaderBuilder.SyncDirection = SyncDirection.DownloadOnly
        orderHeaderBuilder.CreationTrackingColumn = "InsertTimestamp"
        orderHeaderBuilder.UpdateTrackingColumn = "UpdateTimestamp"
        orderHeaderBuilder.DeletionTrackingColumn = "DeleteTimestamp"

        Dim orderHeaderSyncAdapter As SyncAdapter = orderHeaderBuilder.ToSyncAdapter()
        orderHeaderSyncAdapter.TableName = "OrderHeader"
        Me.SyncAdapters.Add(orderHeaderSyncAdapter)

        'Handle the ChangesSelected event, and display
        'information to the console.
        AddHandler Me.ChangesSelected, AddressOf SampleServerSyncProvider_ChangesSelected

    End Sub 'New


    Public Sub SampleServerSyncProvider_ChangesSelected(ByVal sender As Object, ByVal e As ChangesSelectedEventArgs)
        Console.WriteLine("Total number of batches: " & e.Context.BatchCount)
        Console.WriteLine("Changes applied for group " & e.GroupMetadata.GroupName)
        Console.WriteLine("Inserts applied for group: " & e.Context.GroupProgress.TotalInserts.ToString())
        Console.WriteLine("Updates applied for group: " & e.Context.GroupProgress.TotalUpdates.ToString())
        Console.WriteLine("Deletes applied for group: " & e.Context.GroupProgress.TotalDeletes.ToString())

    End Sub 'SampleServerSyncProvider_ChangesSelected
End Class 'SampleServerSyncProvider

'Create a class that is derived from 
'Microsoft.Synchronization.Data.SqlServerCe.SqlCeClientSyncProvider.
Public Class SampleClientSyncProvider
    Inherits SqlCeClientSyncProvider


    Public Sub New()
        'Specify a connection string for the sample client database.
        Dim util As New Utility()
        Me.ConnectionString = Utility.ConnStr_SqlCeClientSync

    End Sub 'New
End Class 'SampleClientSyncProvider

'Handle the statistics that are returned by the SyncAgent.
Public Class SampleStats

    Public Sub DisplayStats(ByVal syncStatistics As SyncStatistics, ByVal syncType As String)
        Console.WriteLine(String.Empty)
        If syncType = "initial" Then
            Console.WriteLine("****** Initial Synchronization Stats ******")
        ElseIf syncType = "subsequent" Then
            Console.WriteLine("***** Subsequent Synchronization Stats ****")
        End If

        Console.WriteLine("Start Time: " & syncStatistics.SyncStartTime)
        Console.WriteLine("Total Changes Downloaded: " & syncStatistics.TotalChangesDownloaded)
        Console.WriteLine("Complete Time: " & syncStatistics.SyncCompleteTime)
        Console.WriteLine(String.Empty)

    End Sub 'DisplayStats
End Class 'SampleStats

请参阅

概念

对常见客户端与服务器同步任务进行编程