SQLDescribeParam

In earlier releases of the Informix® ODBC Driver, the SQLDescribeParam API returned SQL_UNKNOWN if the API was called to get information about an expression value or a parameter that was embedded inside another routine. This restriction no longer applies to values of BOOLEAN, LVARCHAR, or of built-in non-opaque Informix® data types that are returned by the following expressions in other UDRs:

• Binary arithmetic expressions
  • Addition ( + )
  • Subtraction ( - )
  • Multiplication ( * )
  • Division ( / )
• Relational operator expressions
  • Less than ( < )
  • Less than or equal to ( <= )
  • Equal to ( =, == )
  • Greater than or equal to ( >= )
  • Greater than ( > )
  • Not equal to ( <>, != )
• The following string operations
  • Concatenation ( || )
  • MATCHES
  • LIKE
• BETWEEN ... AND conditional expressions

For example, if the column tab1.c1 is an INT data type, SQLDescribeParam() returns type int for the input host variable of the following query:

select c1, c2 from tab1 where  ABS(c1) > ?;

The UDR from the other side of the expression can be a column expression or a built-in routine, but it cannot be a user-defined routine. In earlier releases, the SQLDescribeParam API returns SQL_UNKNOWN for expression values and parameters that are embedded in another procedure in the following cases:

• The value on the other side of the expression is a user-defined routine.
• Another operand of the same expression is a user-defined routine.
• The data type of any operand of the expression is not a BOOLEAN, LVARCHAR, or a built-in non-opaque data type.