A key step in using ArcCatalog is to establish connections to file folders, geodatabases, servers, and other information sources that you plan to use.
Once connected, ArcCatalog helps you manage all your geographic information sets using the Catalog tree. The nodes in the Catalog tree are organized around the various ArcGIS information types. Here is an overview for creating connections to these information types.
Making folder connections
Folders contain a number of GIS elements—for example, map documents (.mxd), layer files (.lyr), toolboxes (.tbx), file and personal geodatabases (.gdb and .mdb), and a number of file-based datasets. The first task for working with folders and their contents is to make a folder connection in ArcCatalog. Here are the steps:
- Navigate to Folder Connections in the Catalog tree.
- Right-click the Folder Connections item and click Connect To Folder.
- Type the path or navigate to the desired workspace folder, then click OK.
Alternatively, folder connections can be made by clicking the Connect To Folder button 
on the Standard toolbar.
Connecting to SQL Server Express geodatabases for administration
Database server connections (
) allow you to administer SQL Server Express geodatabases—create new instances of SQL Server Express geodatabases, add users, set user properties, and so on. See Adding a database server to ArcGIS Desktop to learn more about creating and using database connections for SQL Server Express.
Making database connections to use ArcSDE geodatabases
Database connections (
) allow you to access and use any ArcSDE geodatabase, including SQL Server Express, SQL Server, Oracle, DB2, Informix, and PostgreSQL geodatabases. See Connecting to an ArcSDE geodatabase for more information.
Making GIS server connections
GIS server connections allow you to connect to instances of ArcGIS Server (
), ArcIMS server(
), OGC servers for WMS (
), and WCS (
).
See Connecting to GIS servers to learn how to make each type of connection.
You can also use ArcCatalog to organize services in a series of folders. 
See Adding GIS service folders in ArcCatalog for more information.
Once you have established a server connection, you can click to expand its icon (
) and work with its services. A red x for a server connection (
) indicates that you are currently disconnected from the server. Double-click to reconnect.
Making interoperability connections
Interoperability connections are used to add Data Interoperability formats to ArcGIS. The Data Interoperability extension for ArcGIS enables you to use Safe Software's FME product to add support in ArcGIS for virtually any external geospatial or tabular data format.