如何在Oracle中使用LookUp表？

Table Name: STATE_CODE
ID    DESCRIPTION
=================
1   Alabama
2   Arkansas
...
50  Wyoming

Table Name: CUSTOMER
=====================
CUST_ID   CUST_NAME   CUST_STATE
100       AAA Company          1  --they are in Alabama!
200       ZZZ Company          50 --they are in Wyoming!

--first, create the lookup table
CREATE TABLE STATE_CODE(
  ID INTEGER NOT NULL
 ,DESCRIPTION VARCHAR(100) NOT NULL
 ,PRIMARY KEY(ID)
);

--now add a reference to the lookup table inside your existing table
--the REFERENCES part will **force** entries
--to have a matching entry in STATE_CODE
ALTER TABLE CUSTOMER ADD STATE_CODE_ID REFERENCES STATE_CODE(ID);

INSERT INTO CUSTOMER(CUST_ID,CUST_NAME,CUST_STATE)
VALUES(9000,\'Martians\',74837483748);