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SQL Anywhere 17 » SQL Anywhere Server - Programming

ODBC support

ODBC (Open Database Connectivity) is a standard call level interface (CLI) developed by Microsoft Corporation. It is based on the SQL Access Group CLI specification.

ODBC applications can run against any data source that provides an ODBC driver. ODBC is a good choice for a programming interface if you want your application to be portable to other data sources that have ODBC drivers.

ODBC is a low-level interface. Almost all database server functionality is available with this interface. ODBC is available as a DLL under Windows operating systems. It is provided as a shared object library for Unix.


In this section:
    Requirements for developing ODBC applications
    You can develop applications using a variety of development tools and programming languages, as shown in the figure below, and access the database server using the ODBC API.
    ODBC application development
    Every C/C++ source file that calls ODBC functions must include a platform-specific ODBC header file. Each platform-specific header file includes the main ODBC header file odbc.h, which defines all the functions, data types, and constant definitions required to write an ODBC program.
    Sample ODBC programs
    Sample ODBC programs are included with the software.
    ODBC handles
    ODBC applications use a small set of handles to track the ODBC context, database connections, and SQL statements. A handle is a pointer type and is a 64-bit value in 64-bit applications and a 32-bit value in 32-bit applications.
    ODBC connection functions
    ODBC supplies three different connection functions.
    Server options changed by ODBC
    The ODBC driver sets some temporary server options when connecting to the database server.
    SQLSetConnectAttr extended connection attributes
    The ODBC driver supports some extended connection attributes.
    Considerations for the Windows DllMain function
    ODBC functions should not be called directly or indirectly from the DllMain function in a Windows Dynamic Link Library. The DllMain entry point function is intended to perform only simple initialization and termination tasks. Calling ODBC functions like SQLFreeHandle, SQLFreeConnect, and SQLFreeEnv can create deadlocks and circular dependencies.
    Ways to execute SQL statements
    ODBC includes several functions for executing SQL statements.
    64-bit ODBC considerations
    When you use an ODBC function like SQLBindCol, SQLBindParameter, or SQLGetData, some of the parameters are typed as SQLLEN or SQLULEN in the function prototype.
    Data alignment requirements
    When you use SQLBindCol, SQLBindParameter, or SQLGetData, a C data type is specified for the column or parameter.
    Result sets in ODBC applications
    ODBC applications use cursors to manipulate and update result sets. The software provides extensive support for different kinds of cursors and cursor operations.
    Stored procedure considerations
    You can create and call stored procedures and process the results from an ODBC application.
    ODBC escape syntax
    You can use ODBC escape syntax from any ODBC application. This escape syntax allows you to call a set of common functions regardless of the database management system you are using.
    Error handling in ODBC
    Errors in ODBC are reported using the return value from each of the ODBC function calls and either the SQLError function or the SQLGetDiagRec function.