how to find constraints on a table in oracle

1SELECT cons.OWNER 			AS CHILD_OWNER,
2       cons.TABLE_NAME 		AS CHILD_TABLE,
3       cons.CONSTRAINT_NAME AS CONSTAINT_NAME,
4       cons.CONSTRAINT_TYPE AS CONSTRAINT_TYPE,
5       col.OWNER 			AS PARENT_OWNER,
6       col.TABLE_NAME 		AS PARENT_TABLE,
7       col.COLUMN_NAME 		AS COLUMN_NAME
8FROM DBA_CONS_COLUMNS col, DBA_CONSTRAINTS cons
9WHERE cons.R_OWNER = col.OWNER
10  AND cons.R_CONSTRAINT_NAME = col.CONSTRAINT_NAME
11  AND cons.TABLE_NAME = 'table_name';