Linked Server - SQL Server

A linked server is a SQL Server feature that enables you to connect to other database servers or data sources from within a SQL Server instance. Once you have created a linked server, you can execute distributed queries and transactions against the remote data source as if it were a local table in your database. 

Here are the steps to create a linked server:

  • Open SQL Server Management Studio and connect to the SQL Server instance where you want to create the linked server.
  • In Object Explorer, expand the "Server Objects" node, right-click on the "Linked Servers" node, and select "New Linked Server".
  • In the "New Linked Server" dialog box, enter a name for the linked server and select the data source type, such as SQL Server or Oracle.
  • Enter the connection properties for the remote data source, such as the server name, database name, and authentication method.
  • Configure the security options for the linked server, such as the login mappings and permissions.
  • Test the connection to the linked server to verify that it is configured correctly.

Once you have created a linked server, you can execute distributed queries and transactions against the remote data source using the four-part naming convention. For example, you can query a remote table using the following syntax:

SELECT * FROM [LinkedServerName].[DatabaseName].[SchemaName].[TableName]

You can also execute stored procedures and functions on the remote data source by using the "EXECUTE" statement with the four-part naming convention.

It is important to note that linked servers can have performance and security implications, and should be used with caution. When executing distributed queries, the data is transferred across the network, which can result in slower query performance. Additionally, linked servers can create security risks if they are not configured properly. Therefore, it is recommended to carefully plan and test the use of linked servers in your environment, and to implement best practices for security and performance.

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