Function dbms_sql_define_column

gpcontrib/orafce/dbms_sql.c:750–806

* CREATE PROCEDURE dbms_sql.define_column(c int, col int, value "any", column_size int DEFAULT -1); */

 * CREATE PROCEDURE dbms_sql.define_column(c int, col int, value "any", column_size int DEFAULT -1);
 */
Datum
dbms_sql_define_column(PG_FUNCTION_ARGS)
{
	CursorData *c;
	ColumnData *col;
	Oid			valtype;
	Oid			basetype;
	int		position;
	int		colsize;
	TYPCATEGORY category;
	bool	ispreferred;

	c = get_cursor(fcinfo, true);

	if (PG_ARGISNULL(1))
		ereport(ERROR,
			    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
			     errmsg("column position (number) is NULL")));

	position = PG_GETARG_INT32(1);
	col = get_col(c, position, true);

	valtype = get_fn_expr_argtype(fcinfo->flinfo, 2);
	if (valtype == RECORDOID)
		ereport(ERROR,
			    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
			     errmsg("cannot to define a column of record type")));

	if (valtype == UNKNOWNOID)
		valtype = TEXTOID;

	basetype = getBaseType(valtype);

	if (col->typoid != InvalidOid)
		ereport(ERROR,
			    (errcode(ERRCODE_DUPLICATE_COLUMN),
			     errmsg("column is defined already")));

	col->typoid = valtype;

	if (PG_ARGISNULL(3))
		ereport(ERROR,
			    (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
			     errmsg("column_size is NULL")));

	colsize = PG_GETARG_INT32(3);

	get_type_category_preferred(basetype, &category, &ispreferred);
	col->typisstr = category == TYPCATEGORY_STRING;
	col->typmod = (col->typisstr && colsize != -1) ? colsize + 4 : -1;

	get_typlenbyval(basetype, &col->typlen, &col->typbyval);

	col->rowcount = 1;

	return (Datum) 0;
}