Data type identifiers are stored in the SQL_DESC_CONCISE_TYPE field of a descriptor. Data type identifiers in applications describe their buffers to the driver.
They also retrieve metadata about the result set from the driver so applications know what type of C buffers to use for data storage. Applications use data type identifiers to perform these tasks by calling these functions:
▪ To describe the C data type of application buffers, applications call SQLBindParameter, SQLBindCol, and SQLGetData.
▪ To describe the SQL data type of dynamic parameters, applications call SQLBindParameter.
▪ To retrieve the SQL data types of result set columns, applications call SQLColAttribute and SQLDescribeCol.
▪ To retrieve the SQL data types of parameters, applications call SQLDescribeParameter.
▪ To retrieve the SQL data types of various schema information, applications call SQLColumns, SQLProcedureColumns, and SQLSpecialColumns.
▪ To retrieve a list of supported data types, applications call SQLGetTypeInfo.
In addition, the SQLSetDescField and SQLSetDescRec descriptor functions are also used to perform the above tasks. For details, see the SQLSetDescField and SQLSetDescRec functions.