Local Fetch

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Local Fetch

IBM Informix ODBC Driver performs a local fetch when you retrieve a row or collection from one location on the client computer to another location on the client computer.

To perform a local fetch

Call ifx_rc_create() to allocate a row or collection buffer.
Call SQLBindCol() to bind the buffer handle to the local row or collection.
Execute a SELECT statement to transfer the row or collection data to the local buffer.
For each element in the row or collection, call ifx_rc_fetch() to copy the value to the buffer.
Use the row or collection buffer.
Call ifx_rc_free() to deallocate the buffer.

A local fetch has the following limits on SQL data conversion:

IBM Informix ODBC Driver cannot convert extended data types for which the cast functions are on a database server.
IBM Informix ODBC Driver cannot convert data from one named row type to another. Only the database server can perform this kind of conversion.
IBM Informix ODBC Driver cannot convert SQL data types when retrieving an entire row or collection. Thus, IBM Informix ODBC Driver can perform a local fetch of an entire row or collection only if the internal structures for the source and destination are the same or if the destination is an unfixed-type buffer.
For example, if you define a local collection as list (char(1) not null), the database server can put a list (int not null) value from the database server into the local collection. During this operation, the database server converts each integer into a string and constructs a new list to return to the client computer. You cannot perform this operation on the client computer where you retrieve a local list of integers into a list characters.