Query to find child table of parent table using ALL_CONSTRAINTS
SELECT PK.TABLE_NAME "PRIMARY_KEY_TABLE",
FK.TABLE_NAME "FOREIGN_KEY_TABLE",
PK.CONSTRAINT_NAME "PK_CONSTRAINT_NAME",
FK.CONSTRAINT_NAME "FK_CONSTRAINT_NAME",
(SELECT COLUMN_NAME
FROM ALL_CONS_COLUMNS C
WHERE C.CONSTRAINT_NAME = PK.CONSTRAINT_NAME) "PK_COLUMN",
(SELECT COLUMN_NAME
FROM ALL_CONS_COLUMNS C
WHERE C.CONSTRAINT_NAME = FK.CONSTRAINT_NAME) "FK_COLUMN"
FROM ALL_CONSTRAINTS PK
INNER JOIN ALL_CONSTRAINTS FK
ON PK.CONSTRAINT_NAME = FK.R_CONSTRAINT_NAME
WHERE PK.CONSTRAINT_TYPE IN ('P') AND PK.TABLE_NAME = 'PRIMARY_KEY_DEMO' -- Table name