Note:This topic was updated for 9.3.1.
ArcSDE database server connections are used for the creation and administration of ArcSDE geodatabases for SQL Server Express.
Before you can create geodatabases on a database server in ArcCatalog, you must connect to an ArcSDE database server. (A database server is an instance of SQL Server Express.) This involves the following:
Adding a database server
When you add a database server in the Database Servers folder of the Catalog tree, you create a connection to an existing database server. That means the SQL Server Express instance must already exist and have been enabled to store geodatabases, and your Windows login must already have been added to the instance.
Adding a database server creates a connection file and an icon in the Database Servers folder for that connection. The connection file and icon remain in the Database Servers folder until you delete them, whether or not you are actually connected to the database server. See Adding an ArcSDE database server for further instructions.
Connecting to a database server
You can double-click the database server connection icon in the Catalog tree or right-click it and click Connect to connect to the database server.
When you connect to an ArcSDE database server, you are connecting to a SQL Server Express instance, not to a specific geodatabase.
If you have problems connecting to the database server, make sure the instance is running and that you have permission to access the database server with the current login.
Once you are connected to the database server, if you are a database server administrator, you can create geodatabases. You can create and administer multiple geodatabases on a database server. See the section "How to create a geodatabase on an ArcSDE database server" in the topic Creating a new geodatabase in the "Creating a geodatabase" section of the help.
When you reconnect to your database server, you always initially see the default versions of your geodatabases (DBO.DEFAULT). You can change versions, but if you frequently work with a version other than DEFAULT, you can save some steps by saving a connection to a particular version of the geodatabase.
Saving a geodatabase connection creates a connection file in the Spatial Database Connections folder that points to a particular version of the geodatabase. This allows you to reconnect to that version of the database without having to first connect to the database server and change the version of the geodatabase you are viewing. See Saving a geodatabase connection for instructions.