FAQ: Will I have read-write access to my RDBMS if I use ArcSDE's direct connect drivers?
Will I have read-write access to my RDBMS if I use ArcSDE's direct connect drivers?
ArcSDE 8.1 provides ESRI products with the functionality to access directly your Oracle or SQL Server Database, and hence, the spatial data stored in that database. Direct connect driver support for Informix and DB2 is planned for a later release.
ArcSDE is the database gateway that all ESRI products use to provide RDBMS independent access, and to emulate functionality when the RDBMS cannot support it.
ArcSDE 8.1 supports two modes of connection to the database.
1) A two-tier "direct connect" architecture
ESRI products will be delivered with the components necessary to use the two-tier direct connect architecture out of the box. The ArcSDE client and server functionality are executed on the same hardware machine as the application so there is no separate ArcSDE server process running anywhere. Out of the box, a connection to Oracle or SQL Server through the two-tier direct connect architecture will be read-only. If a site has purchased an ArcSDE server license, a connection to Oracle or SQL Server through the two-tier direct connect architecture will be read-write.
2) A three-tier application server architecture (the only architecture available prior to the release of ArcSDE 8.1)
To use the three-tier architecture, an you must purchase an ArcSDE server license. The client application has to connect to the ArcSDE application server that then connects to the host RDBMS. As stated above, having an ArcSDE server license at a site will also allow all two-tier direct connect users read-write access to the RDBMS.