Answers for "how to create a foreign key in oracle"

how to create table in oracle sql syntax example and foreign key

CREATE TABLE hr.admin_emp (
         empno      NUMBER(5) PRIMARY KEY,
         ename      VARCHAR2(15) NOT NULL,
         ssn        NUMBER(9) ENCRYPT,
         job        VARCHAR2(10),
         mgr        NUMBER(5),
         hiredate   DATE DEFAULT (sysdate),
         photo      BLOB,
         sal        NUMBER(7,2),
         hrly_rate  NUMBER(7,2) GENERATED ALWAYS AS (sal/2080),
         comm       NUMBER(7,2),
         deptno     NUMBER(3) NOT NULL
                     CONSTRAINT admin_dept_fkey REFERENCES hr.departments
                     (department_id))

foreign key on table oracle

SELECT c.OWNER, a.TABLE_NAME, a.COLUMN_NAME, a.CONSTRAINT_NAME, 
       c.R_OWNER AS REF_OWNER, cpk.TABLE_NAME AS REF_TABLE, 
       cpk.CONSTRAINT_NAME AS REF_PK
FROM ALL_CONS_COLUMNS a 
JOIN ALL_CONSTRAINTS c ON a.OWNER = c.OWNER
    AND a.CONSTRAINT_NAME = c.CONSTRAINT_NAME
 JOIN ALL_CONSTRAINTS cpk ON c.R_OWNER = cpk.OWNER
    AND c.R_CONSTRAINT_NAME = cpk.CONSTRAINT_NAME
WHERE c.CONSTRAINT_TYPE = 'R' AND c.TABLE_NAME= 'table_name';