Open Database Connectivity (ODBC) is a standard application programming interface (API) developed by Microsoft. It allows a single application to access a variety of data sources for which ODBC-compliant drivers exist. The application uses Structured Query Language (SQL) as the standard data access language.
The ODBC API defines the following:
A library of ODBC function calls that connect to the data source, execute SQL statements, and retrieve results
A standard way to connect and log in to a DBMS
SQL syntax based on the X/Open and SQL Access Group (SAG) CAE specification (1992)
A standard representation for datatypes
A standard set of error codes
Applications that provide an ODBC interface, like PowerBuilder, can access data sources for which an ODBC driver exists. An ODBC data source driver is a dynamic link library (DLL) that implements ODBC function calls. The application invokes the ODBC driver to access a particular data source.
Using the ODBC interface, PowerBuilder can connect, save, and retrieve data in both ANSI/DBCS and Unicode databases but does not convert data between Unicode and ANSI/DBCS. When character data or command text is sent to the database, PowerBuilder sends a Unicode string. The driver must guarantee that the data is saved as Unicode data correctly. When PowerBuilder retrieves character data, it assumes the data is Unicode.
A Unicode database is a database whose character set is set to a Unicode format, such as UTF-8, UTF-16, UCS-2, or UCS-4. All data must be in Unicode format, and any data saved to the database must be converted to Unicode data implicitly or explicitly.
A database that uses ANSI (or DBCS) as its character set might use special datatypes to store Unicode data. Columns with these datatypes can store only Unicode data. Any data saved into such a column must be converted to Unicode explicitly. This conversion must be handled by the database server or client.
