7. Understanding ODBC Connectivity

The Vector ODBC Driver (subsequently referred to as the ODBC Driver) enables ODBC-enabled applications to access Ingres, Vector, Enterprise Access, and EDBC databases. The driver is installed as part of a standard client installation.

The ODBC Call-level Interface (ODBC CLI) provides access to the ODBC application environment without the need to use third-party software. It is installed when you install the ODBC Driver and is supported on all platforms on which Ingres and Vector run.

The ODBC CLI performs the following functions:

• Optionally determines driver characteristics from ODBC configuration files

• Loads and unloads the ODBC driver into and from application memory

• Provides function templates, type definitions, and constant definitions for ODBC applications

• Provides connection pooling, which allows connections to be shared in ODBC applications.

Note: The ODBC CLI is not a generic ODBC driver manager. While it does provide functions similar to other ODBC driver managers, it is designed specifically to support ODBC-based application access to the Ingres 3.5 ODBC driver. It does not support ODBC drivers provided by third-party vendors.

The ODBC CLI is available on all supported platforms except Windows. The iiodbcadmin utility configures ODBC Data Source Definitions for the CLI. For more information, see Configure a Data Source (Linux).

The ODBC driver does not currently support the following features:

• Translation DLL (Vector handles this requirement through the II_CHARSETxx environment variable.)

• The GUID (Globally Unique Identifier) data type, which is specific to Microsoft Access databases.

On Windows, the Microsoft installer DLL can be used to install the ODBC Driver, if required. The ODBC Driver can be installed from the Ingres, Vector, or Client Runtime installer.

On non-Windows platforms, the odbcinst and iisuodbc utilities use the ODBC Configuration API to configure driver information.

To support the release of a non-configurable read-only driver into production environments, the ODBC driver can optionally be installed as a read-only driver. This driver allows SQL statements such as SELECT, EXECUTE PROCEDURE, and ODBC CALL, but does not allow update statements (for example, INSERT, DELETE, UPDATE, CREATE, and so on).

Both ODBC drivers (read-only and read/update) are installed during the standard Vector installation. Selection of the driver type is performed during configuration of an ODBC data source. For more information, see Configure a Data Source (Windows) and Configure a Data Source (Linux).

The following sections list the ODBC driver software, platform, and protocol requirements. For additional information relating to the ODBC driver, see http://www.actian.com. The ODBC CLI and Driver Manager are packaged with every product release, service pack, and patch.