방법: 세션 변수 사용
이 항목에서는 Sync Framework의 세션 변수를 사용하는 방법에 대해 설명합니다. 이 항목의 예제에서는 다음과 같은 Sync Framework 형식을 중점적으로 설명합니다.
샘플 코드를 실행하는 방법에 대한 자세한 내용은 일반적인 클라이언트 및 서버 동기화 태스크 프로그래밍의 "방법 항목의 예제 응용 프로그램"을 참조하십시오.
세션 변수 이해
Sync Framework는 동기화 중에 SyncAdapter 및 DbServerSyncProvider 명령에 값을 전달하는 데 사용할 수 있는 세션 변수 집합을 제공합니다. 이러한 변수는 ADO.NET 명령에서 쿼리 또는 저장 프로시저에 대해 다른 매개 변수와 마찬가지로 지정됩니다. 동기화 세션 중에 각 ADO.NET 명령 개체가 DbServerSyncProvider에서 호출되면 공급자는 동기화 매개 변수 컬렉션(SyncParameters)을 통해 각 매개 변수가 이름을 기반으로 ADO.NET 명령 매개 변수와 일치하는지 여부를 판단합니다. 기본 제공 세션 변수 또는 사용자가 정의한 사용자 지정 매개 변수와 일치하는 변수가 있으면 공급자가 명령을 호출하기 전에 Sync Framework에서 채워집니다.
예를 들어 다음 쿼리는 sync_last_received_anchor, sync_new_received_anchor 및 sync_client_id 세션 변수를 사용하여 Customer 테이블에서 변경 내용을 선택합니다.
"SELECT CustomerId, CustomerName, SalesPerson, CustomerType FROM
Sales.Customer WHERE InsertTimestamp > @sync_last_received_anchor AND
InsertTimestamp <= @sync_new_received_anchor AND InsertId <>
@sync_client_id"
이러한 변수의 값은 동기화 중에 Sync Framework에서 제공됩니다. 위의 쿼리와 같이 변수 이름을 직접 사용할 수도 있고, SyncSession 개체에서 제공되는 상수를 사용할 수도 있습니다.
"SELECT CustomerId, CustomerName, SalesPerson, CustomerType FROM
Sales.Customer WHERE InsertTimestamp > @" +
SyncSession.SyncLastReceivedAnchor +
" AND InsertTimestamp <= @" +
SyncSession.SyncNewReceivedAnchor +
" AND InsertId <> @"
SyncSession.SyncClientId
다음 표에는 사용 가능한 모든 세션 변수 및 변수의 사용 방법이 나와 있습니다.
| 세션 변수 | 용도 |
|---|---|
sync_client_id, sync_client_id_hash, sync_client_id_binary 및 sync_originator_id |
현재 동기화 중인 클라이언트를 식별하는 데 사용됩니다. ID는 보통 충돌을 검색하고 양방향 동기화 중에 변경 내용이 다시 클라이언트에 에코되지 않도록 하는 데 사용됩니다. 자세한 내용은 방법: 클라이언트와 서버 간에 양방향 증분 데이터 변경 내용 교환을 참조하십시오. 기본적으로 Sync Framework는 sync_client_id에서 반환하는 GUID로 각 클라이언트를 식별합니다. ID의 해시를 만들고 쿼리에서 sync_client_id_hash를 사용할 수도 있습니다. sync_client_id_binary는 SQL Server 변경 내용 추적을 사용하여 변경 내용을 추적할 때 유용합니다. GUID를 sync_client_id에서 정수로 매핑하고 sync_originator_id를 사용할 수 있습니다. 자세한 내용은 이 항목 뒷부분의 "예제" 단원을 참조하십시오. |
sync_last_received_anchor 및 sync_new_received_anchor |
세션 중에 동기화할 변경 내용 집합을 정의하는 데 사용됩니다. 현재 동기화 중에 SelectNewAnchorCommand 속성에 대해 지정되는 명령은 새 앵커 값을 제공합니다. 마지막으로 받은 앵커 값 이후와 새로 받은 앵커 값 이전에 변경된 내용이 동기화됩니다. 그런 다음 새로 받은 앵커가 저장되어 다음 동기화에서 마지막으로 받은 앵커 값으로 사용됩니다. 자세한 내용은 서버 데이터베이스의 변경 내용 추적의 "클라이언트로 다운로드할 데이터 변경 내용 결정"을 참조하십시오. |
sync_force_write |
RetryWithForceWrite의 ApplyAction과 함께 충돌이나 오류로 인해 실패한 변경 내용을 강제로 적용하는 데 사용됩니다. 자세한 내용은 방법: 데이터 충돌 및 오류 처리를 참조하십시오. |
sync_row_count |
서버에서 마지막으로 수행한 작업이 적용된 행의 수를 반환합니다. SQL Server 데이터베이스에서는 @@ROWCOUNT가 이 변수의 값을 제공합니다. 행 개수가 0인 경우 대개 충돌이나 오류 때문에 작업이 실패했음을 나타냅니다. 자세한 내용은 방법: 데이터 충돌 및 오류 처리를 참조하십시오. |
sync_initialized |
현재 동기화가 초기 동기화(값 0)인지 후속 동기화(값 1)인지를 반환합니다. |
sync_table_name 및 sync_group_name |
테이블 이름을 지정해야 하거나 쿼리에서 이름을 그룹화해야 하는 경우 사용됩니다. |
sync_batch_count, sync_batch_size 및 sync_max_received_anchor |
변경 내용을 일괄 적용하는 경우 사용됩니다. 자세한 내용은 방법: 변경 내용의 순서 및 일괄 처리 크기 지정을 참조하십시오. |
sync_session_id |
현재 동기화 세션을 식별하는 GUID 값을 반환합니다. |
예제
다음 코드 예제에서는 Sync Framework 샘플 데이터베이스의 Vendor 테이블을 동기화할 때 세션 변수를 사용하는 방법을 보여 줍니다.
API의 주요 요소
이 단원에서는 세션 변수가 포함되는 API의 주요 부분을 보여 주는 코드 예제를 제공합니다. 다음 코드 예제에서는 sync_new_received_anchor 변수의 값을 설정하는 SelectNewAnchorCommand 속성에 대한 쿼리를 지정합니다. 이 값은 서버 데이터베이스에서 변경 내용을 선택하는 동기화 명령에 사용됩니다.
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
With selectNewAnchorCommand
.CommandText = "SELECT " + newAnchorVariable + " = min_active_rowversion() - 1"
.Parameters.Add(newAnchorVariable, SqlDbType.Timestamp)
.Parameters(newAnchorVariable).Direction = ParameterDirection.Output
.Connection = serverConn
End With
Me.SelectNewAnchorCommand = selectNewAnchorCommand
다음 코드 예제에서는 클라이언트에 적용할 증분 업데이트를 서버에서 선택하는 명령을 지정합니다. 이 명령에는 앵커 변수 및 sync_originator_id 변수가 포함됩니다. sync_originator_id 변수의 값은 SelectClientIdCommand 속성에 대해 지정되는 쿼리에서 제공됩니다. 이 쿼리 및 속성은 이 단원 끝부분에서 설명합니다.
SqlCommand vendorIncrUpdates = new SqlCommand();
vendorIncrUpdates.CommandText =
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " +
"FROM Sales.Vendor " +
"WHERE (UpdateTimestamp > @sync_last_received_anchor " +
"AND UpdateTimestamp <= @sync_new_received_anchor " +
"AND UpdateId <> @sync_originator_id " +
"AND NOT (InsertTimestamp > @sync_last_received_anchor " +
"AND InsertId <> @sync_originator_id))";
vendorIncrUpdates.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorIncrUpdates.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp);
vendorIncrUpdates.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorIncrUpdates.Connection = serverConn;
vendorSyncAdapter.SelectIncrementalUpdatesCommand = vendorIncrUpdates;
Dim vendorIncrUpdates As New SqlCommand()
With vendorIncrUpdates
.CommandText = _
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " _
& "FROM Sales.Vendor " _
& "WHERE (UpdateTimestamp > @sync_last_received_anchor " _
& "AND UpdateTimestamp <= @sync_new_received_anchor " _
& "AND UpdateId <> @sync_originator_id " _
& "AND NOT (InsertTimestamp > @sync_last_received_anchor " _
& "AND InsertId <> @sync_originator_id))"
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.SelectIncrementalUpdatesCommand = vendorIncrUpdates
다음 코드 예제에서는 클라이언트의 업데이트를 서버에 적용하는 명령을 지정합니다. 이 명령에는 앵커 및 ID 변수 외에도 sync_force_write 및 sync_row_count variables가 포함됩니다.
SqlCommand vendorUpdates = new SqlCommand();
vendorUpdates.CommandText =
"UPDATE Sales.Vendor SET " +
"VendorName = @VendorName, CreditRating = @CreditRating, " +
"PreferredVendor = @PreferredVendor, " +
"UpdateId = @sync_originator_id " +
"WHERE (VendorId = @VendorId) " +
"AND (@sync_force_write = 1 " +
"OR (UpdateTimestamp <= @sync_last_received_anchor " +
"OR UpdateId = @sync_originator_id)) " +
"SET @sync_row_count = @@rowcount";
vendorUpdates.Parameters.Add("@VendorName", SqlDbType.NVarChar);
vendorUpdates.Parameters.Add("@CreditRating", SqlDbType.NVarChar);
vendorUpdates.Parameters.Add("@PreferredVendor", SqlDbType.NVarChar);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorUpdates.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncForceWrite, SqlDbType.Bit);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int);
vendorUpdates.Connection = serverConn;
vendorSyncAdapter.UpdateCommand = vendorUpdates;
Dim vendorUpdates As New SqlCommand()
With vendorUpdates
.CommandText = _
"UPDATE Sales.Vendor SET " _
& "VendorName = @VendorName, CreditRating = @CreditRating, " _
& "PreferredVendor = @PreferredVendor, " _
& "UpdateId = @sync_originator_id " _
& "WHERE (VendorId = @VendorId) " _
& "AND (@sync_force_write = 1 " _
& "OR (UpdateTimestamp <= @sync_last_received_anchor " _
& "OR UpdateId = @sync_originator_id)) " _
& "SET @sync_row_count = @@rowcount"
.Parameters.Add("@VendorName", SqlDbType.NVarChar)
.Parameters.Add("@CreditRating", SqlDbType.NVarChar)
.Parameters.Add("@PreferredVendor", SqlDbType.NVarChar)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier)
.Parameters.Add("@" + SyncSession.SyncForceWrite, SqlDbType.Bit)
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.UpdateCommand = vendorUpdates
다음 코드 예제에서는 클라이언트에 적용할 증분 삭제를 서버에서 선택하는 명령을 지정합니다. 이 명령에는 앵커 및 ID 매개 변수 외에도 sync_initialized 변수가 포함됩니다. 이때 행은 후속 동기화의 경우에만 삭제 표식 테이블에서 선택됩니다. 즉, 초기 동기화 동안에는 삭제 테이블의 행이 사용되지 않습니다.
SqlCommand vendorIncrDeletes = new SqlCommand();
vendorIncrDeletes.CommandText =
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " +
"FROM Sales.Vendor_Tombstone " +
"WHERE (@sync_initialized = 1 " +
"AND DeleteTimestamp > @sync_last_received_anchor " +
"AND DeleteTimestamp <= @sync_new_received_anchor " +
"AND DeleteId <> @sync_originator_id)";
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncInitialized, SqlDbType.Bit);
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp);
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorIncrDeletes.Connection = serverConn;
vendorSyncAdapter.SelectIncrementalDeletesCommand = vendorIncrDeletes;
Dim vendorIncrDeletes As New SqlCommand()
With vendorIncrDeletes
.CommandText = _
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " _
& "FROM Sales.Vendor_Tombstone " _
& "WHERE (@sync_initialized = 1 " _
& "AND DeleteTimestamp > @sync_last_received_anchor " _
& "AND DeleteTimestamp <= @sync_new_received_anchor " _
& "AND DeleteId <> @sync_originator_id)"
.Parameters.Add("@" + SyncSession.SyncInitialized, SqlDbType.Bit)
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.SelectIncrementalDeletesCommand = vendorIncrDeletes
다음 코드 예제에서는 클라이언트 ID를 작성기 ID로 매핑하는 명령을 지정합니다. 이 명령이 반드시 필요한 것은 아니지만 Sync Framework에서 사용하는 GUID 대신 정수를 사용하여 클라이언트를 나타내는 것이 유용할 수 있습니다. 저장 프로시저에 대해서는 다음 코드 예제에서 설명합니다.
SqlCommand selectClientIdCommand = new SqlCommand();
selectClientIdCommand.CommandType = CommandType.StoredProcedure;
selectClientIdCommand.CommandText = "usp_GetOriginatorId";
selectClientIdCommand.Parameters.Add("@" + SyncSession.SyncClientId, SqlDbType.UniqueIdentifier);
selectClientIdCommand.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int).Direction = ParameterDirection.Output;
selectClientIdCommand.Connection = serverConn;
this.SelectClientIdCommand = selectClientIdCommand;
Dim selectClientIdCommand As New SqlCommand()
With selectClientIdCommand
.CommandType = CommandType.StoredProcedure
.CommandText = "usp_GetOriginatorId"
.Parameters.Add("@" + SyncSession.SyncClientId, SqlDbType.UniqueIdentifier)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int).Direction = ParameterDirection.Output
.Connection = serverConn
End With
Me.SelectClientIdCommand = selectClientIdCommand
다음 코드 예제에서는 테이블을 읽고 채우는 매핑 테이블 및 저장 프로시저를 만듭니다. 저장 프로시저는 클라이언트 ID(GUID)를 입력으로 사용하며 작성기 ID(정수)를 반환합니다. 매핑 행은 서버에 삽입되며 추가 행은 새 클라이언트 동기화로 추가됩니다. 클라이언트가 한 번 동기화되고 나면 매핑 테이블에는 해당 클라이언트에 대한 항목이 포함됩니다. SyncAdapter 명령은 작성기 ID를 사용하므로 Vendor 테이블의 추적 열은 uniqueidentifier 형식이 아닌 int 형식입니다.
CREATE TABLE IdMapping(
ClientId uniqueidentifier NOT NULL PRIMARY KEY,
OriginatorId int NOT NULL)
GO
--Insert a mapping for the server.
INSERT INTO IdMapping VALUES ('00000000-0000-0000-0000-000000000000', 0)
GO
CREATE PROCEDURE usp_GetOriginatorId
@sync_client_id uniqueidentifier,
@sync_originator_id int out
AS
SELECT @sync_originator_id = OriginatorId FROM IdMapping WHERE ClientId = @sync_client_id
IF ( @sync_originator_id IS NULL )
BEGIN
SELECT @sync_originator_id = MAX(OriginatorId) + 1 FROM IdMapping
INSERT INTO IdMapping VALUES (@sync_client_id, @sync_originator_id)
END
GO
전체 코드 예제
다음의 전체 코드 예제에는 위에서 설명한 코드 예제와 동기화를 수행하는 데 필요한 추가 코드가 포함되어 있습니다. 이 예제를 사용하려면 데이터베이스 공급자용 유틸리티 클래스 방법 항목에 나와 있는 Utility 클래스가 필요합니다.
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.
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 and client.
Utility.MakeDataChangesOnServer("Vendor");
Utility.MakeDataChangesOnClient("Vendor");
//Subsequent synchronization.
syncStatistics = sampleSyncAgent.Synchronize();
sampleStats.DisplayStats(syncStatistics, "subsequent");
//Return the 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();
//Add the Vendor table: specify a synchronization direction of
//Bidirectional, and that an existing table should be dropped.
SyncTable vendorSyncTable = new SyncTable("Vendor");
vendorSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable;
vendorSyncTable.SyncDirection = SyncDirection.Bidirectional;
this.Configuration.SyncTables.Add(vendorSyncTable);
}
}
//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 use a timestamp value
//that is retrieved and stored in the client database.
//During each synchronization, the new anchor value and
//the last anchor value from the previous synchronization
//are used: the set of changes between these upper and
//lower bounds is synchronized.
//
//SyncSession.SyncNewReceivedAnchor is a string constant;
//you could also use @sync_new_received_anchor directly in
//your queries.
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;
//Create a command that enables you to pass in a
//client ID (a GUID) and get back the orginator ID (an integer)
//that is defined in a mapping table on the server.
SqlCommand selectClientIdCommand = new SqlCommand();
selectClientIdCommand.CommandType = CommandType.StoredProcedure;
selectClientIdCommand.CommandText = "usp_GetOriginatorId";
selectClientIdCommand.Parameters.Add("@" + SyncSession.SyncClientId, SqlDbType.UniqueIdentifier);
selectClientIdCommand.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int).Direction = ParameterDirection.Output;
selectClientIdCommand.Connection = serverConn;
this.SelectClientIdCommand = selectClientIdCommand;
//Create a SyncAdapter for the Vendor table, and then define
//the commands to synchronize changes:
//* SelectIncrementalInsertsCommand, SelectIncrementalUpdatesCommand,
// and SelectIncrementalDeletesCommand are used to select changes
// from the server that the client provider then applies to the client.
//* InsertCommand, UpdateCommand, and DeleteCommand are used to apply
// to the server the changes that the client provider has selected
// from the client.
//Create the SyncAdapter
SyncAdapter vendorSyncAdapter = new SyncAdapter("Vendor");
//Select inserts from the server.
//This command includes three session variables:
//@sync_last_received_anchor, @sync_new_received_anchor,
//and @sync_originator_id. The anchor variables are used with
//SelectNewAnchorCommand to determine the set of changes to
//synchronize. In other example code, the commands use
//@sync_client_id instead of @sync_originator_id. In this case,
//@sync_originator_id is used because the SelectClientIdCommand
//is specified.
SqlCommand vendorIncrInserts = new SqlCommand();
vendorIncrInserts.CommandText =
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " +
"FROM Sales.Vendor " +
"WHERE (InsertTimestamp > @sync_last_received_anchor " +
"AND InsertTimestamp <= @sync_new_received_anchor " +
"AND InsertId <> @sync_originator_id)";
vendorIncrInserts.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorIncrInserts.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp);
vendorIncrInserts.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorIncrInserts.Connection = serverConn;
vendorSyncAdapter.SelectIncrementalInsertsCommand = vendorIncrInserts;
//Apply inserts to the server.
//This command includes @sync_row_count, which returns
//a count of how many rows were affected by the
//last database operation. In SQL Server, the variable
//is assigned the value of @@rowcount. The count is used
//to determine whether an operation was successful or
//was unsuccessful due to a conflict or an error.
SqlCommand vendorInserts = new SqlCommand();
vendorInserts.CommandText =
"INSERT INTO Sales.Vendor (VendorId, VendorName, CreditRating, PreferredVendor, InsertId, UpdateId) " +
"VALUES (@VendorId, @VendorName, @CreditRating, @PreferredVendor, @sync_originator_id, @sync_originator_id) " +
"SET @sync_row_count = @@rowcount";
vendorInserts.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier);
vendorInserts.Parameters.Add("@VendorName", SqlDbType.NVarChar);
vendorInserts.Parameters.Add("@CreditRating", SqlDbType.NVarChar);
vendorInserts.Parameters.Add("@PreferredVendor", SqlDbType.NVarChar);
vendorInserts.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorInserts.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int);
vendorInserts.Connection = serverConn;
vendorSyncAdapter.InsertCommand = vendorInserts;
//Select updates from the server
SqlCommand vendorIncrUpdates = new SqlCommand();
vendorIncrUpdates.CommandText =
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " +
"FROM Sales.Vendor " +
"WHERE (UpdateTimestamp > @sync_last_received_anchor " +
"AND UpdateTimestamp <= @sync_new_received_anchor " +
"AND UpdateId <> @sync_originator_id " +
"AND NOT (InsertTimestamp > @sync_last_received_anchor " +
"AND InsertId <> @sync_originator_id))";
vendorIncrUpdates.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorIncrUpdates.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp);
vendorIncrUpdates.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorIncrUpdates.Connection = serverConn;
vendorSyncAdapter.SelectIncrementalUpdatesCommand = vendorIncrUpdates;
//Apply updates to the server.
//This command includes @sync_force_write, which can
//be used to apply changes in case of a conflict.
SqlCommand vendorUpdates = new SqlCommand();
vendorUpdates.CommandText =
"UPDATE Sales.Vendor SET " +
"VendorName = @VendorName, CreditRating = @CreditRating, " +
"PreferredVendor = @PreferredVendor, " +
"UpdateId = @sync_originator_id " +
"WHERE (VendorId = @VendorId) " +
"AND (@sync_force_write = 1 " +
"OR (UpdateTimestamp <= @sync_last_received_anchor " +
"OR UpdateId = @sync_originator_id)) " +
"SET @sync_row_count = @@rowcount";
vendorUpdates.Parameters.Add("@VendorName", SqlDbType.NVarChar);
vendorUpdates.Parameters.Add("@CreditRating", SqlDbType.NVarChar);
vendorUpdates.Parameters.Add("@PreferredVendor", SqlDbType.NVarChar);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorUpdates.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncForceWrite, SqlDbType.Bit);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorUpdates.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int);
vendorUpdates.Connection = serverConn;
vendorSyncAdapter.UpdateCommand = vendorUpdates;
//Select deletes from the server.
//This command includes @sync_initialized, which is
//used to determine whether a client has been
//initialized already. If this variable returns 0,
//this is the first synchronization for this client ID
//or originator ID.
SqlCommand vendorIncrDeletes = new SqlCommand();
vendorIncrDeletes.CommandText =
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " +
"FROM Sales.Vendor_Tombstone " +
"WHERE (@sync_initialized = 1 " +
"AND DeleteTimestamp > @sync_last_received_anchor " +
"AND DeleteTimestamp <= @sync_new_received_anchor " +
"AND DeleteId <> @sync_originator_id)";
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncInitialized, SqlDbType.Bit);
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp);
vendorIncrDeletes.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorIncrDeletes.Connection = serverConn;
vendorSyncAdapter.SelectIncrementalDeletesCommand = vendorIncrDeletes;
//Apply deletes to the server.
SqlCommand vendorDeletes = new SqlCommand();
vendorDeletes.CommandText =
"DELETE FROM Sales.Vendor " +
"WHERE (VendorId = @VendorId) " +
"AND (@sync_force_write = 1 " +
"OR (UpdateTimestamp <= @sync_last_received_anchor " +
"OR UpdateId = @sync_originator_id)) " +
"SET @sync_row_count = @@rowcount " +
"IF (@sync_row_count > 0) BEGIN " +
"UPDATE Sales.Vendor_Tombstone " +
"SET DeleteId = @sync_originator_id " +
"WHERE (VendorId = @VendorId) " +
"END";
vendorDeletes.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier);
vendorDeletes.Parameters.Add("@" + SyncSession.SyncForceWrite, SqlDbType.Bit);
vendorDeletes.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp);
vendorDeletes.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int);
vendorDeletes.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int);
vendorDeletes.Connection = serverConn;
vendorSyncAdapter.DeleteCommand = vendorDeletes;
//Add the SyncAdapter to the server synchronization provider.
this.SyncAdapters.Add(vendorSyncAdapter);
}
}
//Create a class that is derived from
//Microsoft.Synchronization.Data.SqlServerCe.SqlCeClientSyncProvider.
//You can just instantiate the provider directly and associate it
//with the SyncAgent, but here we use this class to handle client
//provider events.
public class SampleClientSyncProvider : SqlCeClientSyncProvider
{
public SampleClientSyncProvider()
{
//Specify a connection string for the sample client database.
Utility util = new Utility();
this.ConnectionString = Utility.ConnStr_SqlCeClientSync;
//We use the CreatingSchema event to change the schema
//by using the API. We use the SchemaCreated event to
//change the schema by using SQL.
this.CreatingSchema +=new EventHandler<CreatingSchemaEventArgs>(SampleClientSyncProvider_CreatingSchema);
this.SchemaCreated +=new EventHandler<SchemaCreatedEventArgs>(SampleClientSyncProvider_SchemaCreated);
}
private void SampleClientSyncProvider_CreatingSchema(object sender, CreatingSchemaEventArgs e)
{
//Set the RowGuid property because it is not copied
//to the client by default. This is also a good time
//to specify literal defaults with .Columns[ColName].DefaultValue,
//but we will specify defaults like NEWID() by calling
//ALTER TABLE after the table is created.
Console.Write("Creating schema for " + e.Table.TableName + " | ");
e.Schema.Tables["Vendor"].Columns["VendorId"].RowGuid = true;
}
private void SampleClientSyncProvider_SchemaCreated(object sender, SchemaCreatedEventArgs e)
{
//Call ALTER TABLE on the client. This must be done
//over the same connection and within the same
//transaction that Sync Framework uses
//to create the schema on the client.
Utility util = new Utility();
Utility.MakeSchemaChangesOnClient(e.Connection, e.Transaction, e.Table.TableName);
Console.WriteLine("Schema created for " + e.Table.TableName);
}
}
//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 ******");
}
else if (syncType == "subsequent")
{
Console.WriteLine("***** Subsequent Synchronization ****");
}
Console.WriteLine("Start Time: " + syncStatistics.SyncStartTime);
Console.WriteLine("Total Changes Uploaded: " + syncStatistics.TotalChangesUploaded);
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.
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 and client.
Utility.MakeDataChangesOnServer("Vendor")
Utility.MakeDataChangesOnClient("Vendor")
'Subsequent synchronization.
syncStatistics = sampleSyncAgent.Synchronize()
sampleStats.DisplayStats(syncStatistics, "subsequent")
'Return the 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()
'Add the Vendor table: specify a synchronization direction of
'Bidirectional, and that an existing table should be dropped.
Dim vendorSyncTable As New SyncTable("Vendor")
vendorSyncTable.CreationOption = TableCreationOption.DropExistingOrCreateNewTable
vendorSyncTable.SyncDirection = SyncDirection.Bidirectional
Me.Configuration.SyncTables.Add(vendorSyncTable)
End Sub 'New
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 use a timestamp value
'that is retrieved and stored in the client database.
'During each synchronization, the new anchor value and
'the last anchor value from the previous synchronization
'are used: the set of changes between these upper and
'lower bounds is synchronized.
'
'SyncSession.SyncNewReceivedAnchor is a string constant;
'you could also use @sync_new_received_anchor directly in
'your queries.
Dim selectNewAnchorCommand As New SqlCommand()
Dim newAnchorVariable As String = "@" + SyncSession.SyncNewReceivedAnchor
With selectNewAnchorCommand
.CommandText = "SELECT " + newAnchorVariable + " = min_active_rowversion() - 1"
.Parameters.Add(newAnchorVariable, SqlDbType.Timestamp)
.Parameters(newAnchorVariable).Direction = ParameterDirection.Output
.Connection = serverConn
End With
Me.SelectNewAnchorCommand = selectNewAnchorCommand
'Create a command that enables you to pass in a
'client ID (a GUID) and get back the orginator ID (an integer)
'that is defined in a mapping table on the server.
Dim selectClientIdCommand As New SqlCommand()
With selectClientIdCommand
.CommandType = CommandType.StoredProcedure
.CommandText = "usp_GetOriginatorId"
.Parameters.Add("@" + SyncSession.SyncClientId, SqlDbType.UniqueIdentifier)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int).Direction = ParameterDirection.Output
.Connection = serverConn
End With
Me.SelectClientIdCommand = selectClientIdCommand
'Create a SyncAdapter for the Vendor table, and then define
'the commands to synchronize changes:
'* SelectIncrementalInsertsCommand, SelectIncrementalUpdatesCommand,
' and SelectIncrementalDeletesCommand are used to select changes
' from the server that the client provider then applies to the client.
'* InsertCommand, UpdateCommand, and DeleteCommand are used to apply
' to the server the changes that the client provider has selected
' from the client.
'Create the SyncAdapter
Dim vendorSyncAdapter As New SyncAdapter("Vendor")
'Select inserts from the server.
'This command includes three session variables:
'@sync_last_received_anchor, @sync_new_received_anchor,
'and @sync_originator_id. The anchor variables are used with
'SelectNewAnchorCommand to determine the set of changes to
'synchronize. In other example code, the commands use
'@sync_client_id instead of @sync_originator_id. In this case,
'@sync_originator_id is used because the SelectClientIdCommand
'is specified.
Dim vendorIncrInserts As New SqlCommand()
With vendorIncrInserts
.CommandText = _
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " _
& "FROM Sales.Vendor " _
& "WHERE (InsertTimestamp > @sync_last_received_anchor " _
& "AND InsertTimestamp <= @sync_new_received_anchor " _
& "AND InsertId <> @sync_originator_id)"
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.SelectIncrementalInsertsCommand = vendorIncrInserts
'Apply inserts to the server.
'This command includes @sync_row_count, which returns
'a count of how many rows were affected by the
'last database operation. In SQL Server, the variable
'is assigned the value of @@rowcount. The count is used
'to determine whether an operation was successful or
'was unsuccessful due to a conflict or an error.
Dim vendorInserts As New SqlCommand()
With vendorInserts
.CommandText = _
"INSERT INTO Sales.Vendor (VendorId, VendorName, CreditRating, PreferredVendor, InsertId, UpdateId) " _
& "VALUES (@VendorId, @VendorName, @CreditRating, @PreferredVendor, @sync_originator_id, @sync_originator_id) " _
& "SET @sync_row_count = @@rowcount"
.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier)
.Parameters.Add("@VendorName", SqlDbType.NVarChar)
.Parameters.Add("@CreditRating", SqlDbType.NVarChar)
.Parameters.Add("@PreferredVendor", SqlDbType.NVarChar)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.InsertCommand = vendorInserts
'Select updates from the server
Dim vendorIncrUpdates As New SqlCommand()
With vendorIncrUpdates
.CommandText = _
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " _
& "FROM Sales.Vendor " _
& "WHERE (UpdateTimestamp > @sync_last_received_anchor " _
& "AND UpdateTimestamp <= @sync_new_received_anchor " _
& "AND UpdateId <> @sync_originator_id " _
& "AND NOT (InsertTimestamp > @sync_last_received_anchor " _
& "AND InsertId <> @sync_originator_id))"
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.SelectIncrementalUpdatesCommand = vendorIncrUpdates
'Apply updates to the server.
'This command includes @sync_force_write, which can
'be used to apply changes in case of a conflict.
Dim vendorUpdates As New SqlCommand()
With vendorUpdates
.CommandText = _
"UPDATE Sales.Vendor SET " _
& "VendorName = @VendorName, CreditRating = @CreditRating, " _
& "PreferredVendor = @PreferredVendor, " _
& "UpdateId = @sync_originator_id " _
& "WHERE (VendorId = @VendorId) " _
& "AND (@sync_force_write = 1 " _
& "OR (UpdateTimestamp <= @sync_last_received_anchor " _
& "OR UpdateId = @sync_originator_id)) " _
& "SET @sync_row_count = @@rowcount"
.Parameters.Add("@VendorName", SqlDbType.NVarChar)
.Parameters.Add("@CreditRating", SqlDbType.NVarChar)
.Parameters.Add("@PreferredVendor", SqlDbType.NVarChar)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier)
.Parameters.Add("@" + SyncSession.SyncForceWrite, SqlDbType.Bit)
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.UpdateCommand = vendorUpdates
'Select deletes from the server.
'This command includes @sync_initialized, which is
'used to determine whether a client has been
'initialized already. If this variable returns 0,
'this is the first synchronization for this client ID
'or originator ID.
Dim vendorIncrDeletes As New SqlCommand()
With vendorIncrDeletes
.CommandText = _
"SELECT VendorId, VendorName, CreditRating, PreferredVendor " _
& "FROM Sales.Vendor_Tombstone " _
& "WHERE (@sync_initialized = 1 " _
& "AND DeleteTimestamp > @sync_last_received_anchor " _
& "AND DeleteTimestamp <= @sync_new_received_anchor " _
& "AND DeleteId <> @sync_originator_id)"
.Parameters.Add("@" + SyncSession.SyncInitialized, SqlDbType.Bit)
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncNewReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.SelectIncrementalDeletesCommand = vendorIncrDeletes
'Apply deletes to the server.
Dim vendorDeletes As New SqlCommand()
With vendorDeletes
.CommandText = _
"DELETE FROM Sales.Vendor " _
& "WHERE (VendorId = @VendorId) " _
& "AND (@sync_force_write = 1 " _
& "OR (UpdateTimestamp <= @sync_last_received_anchor " _
& "OR UpdateId = @sync_originator_id)) " _
& "SET @sync_row_count = @@rowcount " _
& "IF (@sync_row_count > 0) BEGIN " _
& "UPDATE Sales.Vendor_Tombstone " _
& "SET DeleteId = @sync_originator_id " _
& "WHERE (VendorId = @VendorId) " _
& "END"
.Parameters.Add("@VendorId", SqlDbType.UniqueIdentifier)
.Parameters.Add("@" + SyncSession.SyncForceWrite, SqlDbType.Bit)
.Parameters.Add("@" + SyncSession.SyncLastReceivedAnchor, SqlDbType.Timestamp)
.Parameters.Add("@" + SyncSession.SyncOriginatorId, SqlDbType.Int)
.Parameters.Add("@" + SyncSession.SyncRowCount, SqlDbType.Int)
.Connection = serverConn
End With
vendorSyncAdapter.DeleteCommand = vendorDeletes
'Add the SyncAdapter to the server synchronization provider.
Me.SyncAdapters.Add(vendorSyncAdapter)
End Sub 'New
End Class 'SampleServerSyncProvider
'Create a class that is derived from
'Microsoft.Synchronization.Data.SqlServerCe.SqlCeClientSyncProvider.
'You can just instantiate the provider directly and associate it
'with the SyncAgent, but here we use this class to handle client
'provider events.
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
'We use the CreatingSchema event to change the schema
'by using the API. We use the SchemaCreated event to
'change the schema by using SQL.
AddHandler Me.CreatingSchema, AddressOf SampleClientSyncProvider_CreatingSchema
AddHandler Me.SchemaCreated, AddressOf SampleClientSyncProvider_SchemaCreated
End Sub 'New
Private Sub SampleClientSyncProvider_CreatingSchema(ByVal sender As Object, ByVal e As CreatingSchemaEventArgs)
'Set the RowGuid property because it is not copied
'to the client by default. This is also a good time
'to specify literal defaults with .Columns[ColName].DefaultValue,
'but we will specify defaults like NEWID() by calling
'ALTER TABLE after the table is created.
Console.Write("Creating schema for " + e.Table.TableName + " | ")
e.Schema.Tables("Vendor").Columns("VendorId").RowGuid = True
End Sub 'SampleClientSyncProvider_CreatingSchema
Private Sub SampleClientSyncProvider_SchemaCreated(ByVal sender As Object, ByVal e As SchemaCreatedEventArgs)
'Call ALTER TABLE on the client. This must be done
'over the same connection and within the same
'transaction that Sync Framework uses
'to create the schema on the client.
Dim util As New Utility()
Utility.MakeSchemaChangesOnClient(e.Connection, e.Transaction, e.Table.TableName)
Console.WriteLine("Schema created for " + e.Table.TableName)
End Sub 'SampleClientSyncProvider_SchemaCreated
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 ******")
ElseIf syncType = "subsequent" Then
Console.WriteLine("***** Subsequent Synchronization ****")
End If
Console.WriteLine("Start Time: " & syncStatistics.SyncStartTime)
Console.WriteLine("Total Changes Uploaded: " & syncStatistics.TotalChangesUploaded)
Console.WriteLine("Total Changes Downloaded: " & syncStatistics.TotalChangesDownloaded)
Console.WriteLine("Complete Time: " & syncStatistics.SyncCompleteTime)
Console.WriteLine(String.Empty)
End Sub 'DisplayStats
End Class 'SampleStats