A quick tour of connections to ArcSDE geodatabases
To access the data in an ArcSDE geodatabase, client applications must connect to the geodatabase. The connections can be made directly to the geodatabase or using an ArcSDE service.
A direct connection to a geodatabase is one that is made using the database management system's (DBMS) connection methods and direct-connect drivers in the client application. The connection is made directly from the client to the DBMS without the use of an ArcSDE service. Direct connections are also known as two-tiered connections.
An ArcSDE service, also known as an application server or a three-tiered architecture, conveys spatial data between GIS applications and a geodatabase.
Connecting from ArcGIS Desktop
Connections to ArcSDE geodatabases are made through the Database Connections node in the Catalog tree. The following topics explain how to make a connection from ArcGIS Desktop to an ArcSDE geodatabase:
Connecting from ArcIMS
You set up connections from ArcIMS to an ArcSDE geodatabase using the ArcSDE Connection dialog box. See the ArcIMS help for complete instructions. You can also see the basic instructions in Making a connection from ArcIMS to a geodatabase in PostgreSQL
Connection information in administration commands
You provide connection information for a direct connection or ArcSDE service connection using the -i option when connecting from most ArcSDE administration commands. If you are connecting to any database management system other than Oracle, you also provide the -D option with the database name when connecting from administration commands.
If the geodatabase is on a server different from the one on which you are executing the command (a remote server), you must also supply the -s option with the name of the data source. This is usually the server, but for some databases, it is the instance name.
See the ArcSDE Administration Command Reference, which is included with the ArcSDE component of ArcGIS Server Enterprise. See Direct connections from ArcSDE commands to a geodatabase in PostgreSQL for information on using a direct connection from administration commands to an ArcSDE geodatabase.
Connecting from a SQL application
When you connect to a geodatabase using SQL, you open a SQL application, such as Management Studio for SQL Server, a PL/SQL prompt for PostgreSQL, or SQL*Plus for Oracle, and connect as a particular database user. See your DBMS documentation for instructions on using its SQL interfaces.