Parameter Binding Offsets

An application can specify that an offset is added to bound parameter buffer addresses and the corresponding length/indicator buffer addresses when SQLExecDirect or SQLExecute is called. The result of these additions determines the addresses used in these operations.

Bind offsets allow an application to change bindings without calling SQLBindParameter for previously bound parameters. A call to SQLBindParameter to rebind a parameter changes the buffer address and the length/indicator pointer. Rebinding with an offset, on the other hand, simply adds an offset to the existing bound parameter buffer address and length/indicator buffer address. When offsets are used, the bindings are a “template” of how the application buffers are laid out and the application can move this “template” to different areas of memory by changing the offset. A new offset can be specified at any time, and is always added to the originally bound values.

To specify a bind offset, the application sets the SQL_ATTR_PARAM_BIND_OFFSET_PTR statement attribute to the address of an SQLINTEGER buffer. Before the application calls a function that uses the bindings, it places an offset in bytes in this buffer, as long as neither the parameter buffer address nor the length/indicator buffer address is 0, and the bound parameter is in the SQL statement. The sum of the address and the offset must be a valid address. (This means that either or both of the offset and the address to which the offset is added, can be invalid, as long as the sum of them is a valid address.)

Note Binding offsets are not supported by ODBC 2.x drivers.