ECDA Option for ODBC is a Symmetric Multiprocessing (SMP) Sybase Open Server application that uses an Open Server thread for each incoming client connection. It communicates with ASE using the server class direct_connect.
In ECDA Option for ODBC, the DirectConnect server provides the framework in which the service libraries operate. Within the service libraries, each access service accesses data from a particular target, such as DB2 UDB, Microsoft SQL Server, and ODBC-accessible databases.
These rules define the relationship between an access service library and an access service:
A single access service library can support multiple access services.
Each access service has one configuration set and is always associated with a specific access service library.
All access services within a given access service library share the same configuration properties.
You can assign different configuration property values to different access services within an access service library.
When a client connects, the access service logs in to the target database, using the client user ID and password, plus the ODBC-configured data source name (DSN).
Figure 2-1 shows the relationship of the access service library with components of the client workstation, LAN, ODBC driver, and target database.
Figure 2-1: ECDA Option for ODBC architecture
As shown, the request from a client application goes over the LAN to the DirectConnect server. The access service routes the request through the ODBC driver to the target and accesses data from the database. DirectConnect Manager accesses the administrative service library to manage the DirectConnect server and provide a view of the servers, service libraries, and services.
