Function db_postgres_get_columns

modules/db_postgres/res.c:81–177

* Get and convert columns from a result set */

 * Get and convert columns from a result set
 */
int db_postgres_get_columns(const db_con_t* _h, db_res_t* _r)
{
	int col, datatype;

	if (!_h || !_r)  {
		LM_ERR("invalid parameter value\n");
		return -1;
	}

	/* Get the number of rows (tuples) in the query result. */
	RES_ROW_N(_r) = PQntuples(CON_RESULT(_h));

	/* Get the number of columns (fields) in each row of the query result. */
	RES_COL_N(_r) = PQnfields(CON_RESULT(_h));

	if (!RES_COL_N(_r)) {
		LM_DBG("no columns returned from the query\n");
		return -2;
	} else {
		LM_DBG("%d columns returned from the query\n", RES_COL_N(_r));
	}

	if (db_allocate_columns(_r, RES_COL_N(_r)) != 0) {
		LM_ERR("could not allocate columns\n");
		return -3;
	}

	/* For each column both the name and the OID number of the
	 * data type are saved. */
	for(col = 0; col < RES_COL_N(_r); col++) {

		/* The pointer that is here returned is part of the result structure.*/
		RES_NAMES(_r)[col]->s = PQfname(CON_RESULT(_h), col);
		RES_NAMES(_r)[col]->len = strlen(PQfname(CON_RESULT(_h), col));

		LM_DBG("RES_NAMES(%p)[%d]=[%.*s]\n", RES_NAMES(_r)[col], col,
				RES_NAMES(_r)[col]->len, RES_NAMES(_r)[col]->s);

		/* get the datatype of the column */
		switch(datatype = PQftype(CON_RESULT(_h),col))
		{
			case INT2OID:
			case INT4OID:
				LM_DBG("use DB_INT result type\n");
				RES_TYPES(_r)[col] = DB_INT;
			break;

			case INT8OID:
				LM_DBG("use DB_BIGINT result type\n");
				RES_TYPES(_r)[col] = DB_BIGINT;
			break;

			case FLOAT4OID:
			case FLOAT8OID:
			case NUMERICOID:
				LM_DBG("use DB_DOUBLE result type\n");
				RES_TYPES(_r)[col] = DB_DOUBLE;
			break;