Replication Management Objects Concepts

Artikel
05/07/2012

Replication Management Objects (RMO) is a managed code assembly that encapsulates replication functionalities for SQL Server. RMO is implemented by the Microsoft.SqlServer.Replication namespace.

The topics in the following sections describe how you can use RMO to programmatically control replication tasks:

Configure Distribution
Topics in this section show how to use RMO to configure publishing and distribution.
Create, Modify, and Delete Publications and Articles (Replication)
Topics in this section show how to use RMO to create, delete, and modify publications and articles.
Subscribe to Publications
Topics in this section show how to use RMO to create, delete, and modify subscriptions.
Secure a Replication Topology
Topics in this section show how to use RMO to view and modify security settings.
Synchronize Subscriptions (Replication)
Topics in this section show how to synchronize subscriptions.
Monitoring Replication
Topics in this section show how to programmatically monitor a replication topology.

Introduction to RMO Programming

RMO is designed for programming all aspects of SQL Server replication. The RMO namespace is Microsoft.SqlServer.Replication, and it is implemented by the Microsoft.SqlServer.Rmo.dll, which is a Microsoft .NET Framework assembly. The Microsoft.SqlServer.Replication.dll assembly, which also belongs to the Microsoft.SqlServer.Replication namespace, implements a managed code interface for programming the various replication agents (Snapshot Agent, Distribution Agent, and Merge Agent). Its classes can be accessed from RMO to synchronize subscriptions. Classes in the Microsoft.SqlServer.Replication.BusinessLogicSupport namespace, implemented by the Microsoft.SqlServer.Replication.BusinessLogicSupport.dll assembly, are used to create custom business logic for merge replication. This assembly is independent from RMO.

Deploying Applications Based on RMO

RMO depends on the replication components and client connectivity components that are included with all versions of SQL Server except SQL Server Compact. To deploy an application based on RMO, you must install a version of SQL Server that includes replication components and client connectivity components on the computer on which the application will run.

Getting Started with RMO

This section describes how to start a simple RMO project using Microsoft Visual Studio.

To create a new Microsoft Visual C# project

Start Visual Studio.
On the File menu, click New Project. The New Project dialog box appears.
In the Project Types dialog box, select Visual C# Projects. In the Templates pane, select Windows Application.
(Optional) In Name, type the name of the new application.
Click OK to load the Visual C# Windows template.
On the Project menu, select Add Reference item. The Add Reference dialog box appears.
Select the following assemblies from the list on the .NET tab, and then click OK.
- Microsoft.SqlServer.Replication .NET Programming Interface
- Microsoft.SqlServer.ConnectionInfo
- Replication Agent Library
Note

Use the CTRL key to select more than one file.
(Optional) Repeat step 6. Click the Browse tab, navigate to C:\Program Files\Microsoft SQL Server\110\COM, select Microsoft.SqlServer.Replication.BusinessLogicSupport.dll, and then click OK.
On the View menu, click Code.

In the code, before the namespace statement, type the following using statements to qualify the types in the RMO namespaces:

// These namespaces are required.
using Microsoft.SqlServer.Replication;
using Microsoft.SqlServer.Management.Common;
// This namespace is only used when creating custom business
// logic for merge replication.
using Microsoft.SqlServer.Replication.BusinessLogicSupport;

To create a new Microsoft Visual Basic .NET project

Start Visual Studio.
On the File menu, select New Project. The New Project dialog box appears.
In the Project Types pane, select Visual Basic. In the Templates pane, select Windows Application.
(Optional) In the Name box, type the name of the new application.
Click OK to load the Visual Basic Windows template.
On the Project menu, select Add Reference. The Add Reference dialog box appears.
Select the following assemblies from the list on the .NET tab, and then click OK.
- Microsoft.SqlServer.Replication .NET Programming Interface
- Microsoft.SqlServer.ConnectionInfo
- Replication Agent Library
Note

Use the CTRL key to select more than one file.
(Optional) Repeat step 6. Click the Browse tab, navigate to C:\Program Files\Microsoft SQL Server\110\COM, select Microsoft.SqlServer.Replication.BusinessLogicSupport.dll, and then click OK.
On the View menu, click Code.

In the code, before any declarations, type the following Imports statements to qualify the types in the RMO namespaces.

' These namespaces are required.
Imports Microsoft.SqlServer.Replication
Imports Microsoft.SqlServer.Management.Common
' This namespace is only used when creating custom business
' logic for merge replication.
Imports Microsoft.SqlServer.Replication.BusinessLogicSupport

Connecting to a Replication Server

RMO programming objects require that a connection to an instance of SQL Server is made by using an instance of the ServerConnection class. This connection to the server is made independently of any RMO programming objects. It is then passed to the RMO object either during instance creation or by assignment to the ConnectionContext property of the object. In this manner, an RMO programming object and the connection object instances can be created and managed separately, and a single connection object can be reused with multiple RMO programming objects. The following rules apply for connections to a replication server:

All properties for the connection are defined for a given ServerConnection object.
A connection to each instance of SQL Server must have its own ServerConnection object.
The ServerConnection object is assigned to the ConnectionContext property of the RMO programming object being created or accessed on the server.
The Connect method opens the connection to the server. This method must be called before calling any methods that access the server on any RMO programming objects using the connection.
Because RMO and SQL Server Management Objects (SMO) both use the ServerConnection class for connections to SQL Server, the same connection can be used by both RMO and SMO objects. For more information, see Connecting to an Instance of SQL Server.
All authentication information to make the connection and successfully log on to the server is supplied in the ServerConnection object.
Windows Authentication is the default. To use SQL Server Authentication, LoginSecure must be set to false and Login and Password must be set to a valid SQL Server logon and password. Security credentials must always be stored and handled securely, and supplied at run-time whenever possible.
For multithreaded applications, a separate ServerConnection object should be used in each thread.

Call the Disconnect method on the ServerConnection object to close active server connections used by RMO objects.

Setting RMO Properties

The properties of RMO programming objects represent the properties of these replication objects at the server. When creating new replication objects at the server, RMO properties are used to define these objects. For existing objects, the RMO properties represent the existing object's properties, which can be modified only for properties that are writable or settable. Properties can be set on new objects or existing objects.

Setting Properties for New Replication Objects

When creating a new replication object at the server, you must specify all required properties before calling the Create method of the object. For more information about setting properties for a new replication object, see Configure Publishing and Distribution.

Setting Properties for Existing Replication Objects

For replication objects that exist at the server, depending on the object, RMO might support the ability to change some or all of its properties. Only writable or settable properties can be changed. Before properties can be changed, either the Load or the LoadProperties method must be called to get the current properties from the server. Calling these methods indicates that an existing object is being modified.

By default, when changing object properties, RMO commits these changes to the server based on the execution mode of the ServerConnection being used. The IsExistingObject method can be used to verify that an object exists at the server before attempting to retrieve or change its properties. For more information about changing the properties of a replication object, see View and Modify Distributor and Publisher Properties.

Note

When multiple RMO clients or multiple instances of an RMO programming object are accessing the same replication object at the server, the Refresh method of the RMO object can be called to update the properties based on the current state of the object at the server.

Caching Property Changes

When the SqlExecutionModes property is set to CaptureSql all Transact-SQL statements generated by RMO are captured so that they can be executed manually in a single batch by using one of the execution methods. RMO lets you cache property changes and commit them together in a single batch by using the CommitPropertyChanges method of the object. To cache property changes, the CachePropertyChanges property of the object must be set to true. When caching property changes in RMO, the ServerConnection object still controls when changes are sent to the server. For more information about caching property changes for a replication object, see View and Modify Distributor and Publisher Properties.

Important

Although the ServerConnection class supports declaring explicit transactions when setting properties, such transactions may interfere with internal replication transactions, can produce unanticipated results, and should not be used with RMO.

Example

This example demonstrates the caching of property changes. Changes made to the attributes of a transactional publication are cached until they are explicitly sent to the server.

            // Define the server, database, and publication names
            string publisherName = publisherInstance;
            string publicationName = "AdvWorksProductTran";
            string publicationDbName = "AdventureWorks2012";

            TransPublication publication;

            // Create a connection to the Publisher.
            ServerConnection conn = new ServerConnection(publisherName);

            try
            {
                // Connect to the Publisher.
                conn.Connect();

                // Set the required properties for the publication.
                publication = new TransPublication();
                publication.ConnectionContext = conn;
                publication.Name = publicationName;
                publication.DatabaseName = publicationDbName;

                // Explicitly enable caching of property changes on this object.
                publication.CachePropertyChanges = true;

                // If we can't get the properties for this publication, 
                // throw an application exception.
                if (publication.LoadProperties())
                {
                    // Enable support for push subscriptions and disable support 
                    // for pull subscriptions.
                    if ((publication.Attributes & PublicationAttributes.AllowPull) != 0)
                    {
                        publication.Attributes ^= PublicationAttributes.AllowPull;
                    }
                    if ((publication.Attributes & PublicationAttributes.AllowPush) == 0)
                    {
                        publication.Attributes |= PublicationAttributes.AllowPush;
                    }

                    // Send changes to the server.
                    publication.CommitPropertyChanges();
                }
                else
                {
                    throw new ApplicationException(String.Format(
                        "Settings could not be retrieved for the publication. " +
                        "Ensure that the publication {0} exists on {1}.",
                        publicationName, publisherName));
                }
            }
            catch (Exception ex)
            {
                // Do error handling here.
                throw new ApplicationException(
                    "The publication property could not be changed.", ex);
            }
            finally
            {
                conn.Disconnect();
            }

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