Returns precision of the field with col index (1-based).
For FLOAT columns precision is nonzero and scale is -127. If precision is 0, then columnt is NUMBER. Else it's NUMBER(precision, scale).
Note: This function was renamed to oci_field_precision() after PHP >= 5.0.0. For downward compatibility ocicolumnprecision() can also be used. This is deprecated, however.