ingres_field_precision() returns the precision
of a field. This value is used only for decimal, float and money
SQL data types. For detailed information, see the Ingres/OpenAPI
User Guide - Appendix C.
Parameters
index
index
is the number of the field and must
be between 1 and the value given by
ingres_num_fields().
link
The connection link identifier. If not specified, the last opened link
is used.