Understanding ODBC Connectivity

This chapter introduces the Ingres ODBC components that enable ODBC connectivity to Ingres data sources. It provides a description of each component, a list of supported API features, data source configuration instructions, connection string keyword definitions, and guidelines for implementing ODBC-enabled applications in the Ingres environment.

ODBC Driver

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

ODBC Call-level Interface

The Ingres 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 Ingres ODBC Driver and is supported on all platforms on which Ingres runs.

The Ingres 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
• Maps the driver manager API to the driver API
• Performs basic error checking
• Provides thread safety
• Provides ODBC tracing
• Provides function templates, type definitions, and constant definitions for 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 Ingres ODBC drivers provided by third-party vendors.

The ODBC CLI can use ODBC data sources configured with the Microsoft ODBC Administrator on Windows or the iiodbcadmn utility on non-Windows platforms. For more information, see Configure a Data Source (Windows) and Configure a Data Source (UNIX and VMS).

Unsupported ODBC Features

The ODBC driver does not currently support the following features:

• Executing functions asynchronously
• Translation DLL (Ingres handles this requirement through the II_CHARSETxx environment variable.)
• The GUID (Globally Unique Identifier) data type, which is specific to Microsoft Access databases.
• Installer DLL

  On Windows, the Microsoft installer DLL can be used to install the Ingres ODBC driver, if required. The Ingres ODBC driver can be installed from the Ingres installer software or the Ingres ODBC Standalone Patch Installer.

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

• SQLBulkOperations()
• SQLSetPos()

Read-Only Driver Option

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 SET 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 Ingres 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 (UNIX and VMS).