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CREATE
This statement is used to Create an empty Table.
Syntax ::
CREATE TABLE < TABLE > (
<COLUMN1> <DATA TYPE> [NOT NULL] [UNIQUE] [<COLUMN CONSTRAINT],
........
< COLUMNX> <DATA TYPE> [NOT NULL] [UNIQUE] [<COLUMN CONSTRAINT>],
[<TABLE CONSTRAINTS>]
);
Example 1:: NOT NULL
CREATE TABLE CUSTOMER (
CUST_ID NUMBER(3) NOT NULL,
CUST_NAME VARCHAR2(20) ,
CUST_ADDRESS VARCHAR2(30) ,
CUST_CITY VARCHAR(20) ,
CUST_STATE VARCHAR(20) ,
CUST_PIN NUMBER(7) ,
CUST_COUNTRY VARCHAR(10) );
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Example 2:: PRIMARYKEY CONSTRAINT
CREATE TABLE CUSTOMER (
CUST_ID NUMBER(3) ,
CUST_NAME VARCHAR2(20) ,
CUST_ADDRESS VARCHAR2(30) ,
CUST_CITY VARCHAR(20) ,
CUST_STATE VARCHAR(20) ,
CUST_PIN NUMBER(7) ,
CUST_COUNTRY VARCHAR(10)
CONSTRAINT CUSTID_PK PRIMARYKEY (CUST_ID) );
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Example 2:: FOREIGNKEY CONSTRAINT
CREATE TABLE CUSTOMER (
CUST_ID NUMBER(3) ,
CUST_NAME VARCHAR2(20) ,
CUST_ADDRESS VARCHAR2(30) ,
CUST_CITY VARCHAR(20) ,
CUST_STATE VARCHAR(20) ,
CUST_PIN NUMBER(7) ,
CUST_COUNTRY VARCHAR(10)
CONSTRAINT CUSTID_PK PRIMARYKEY (CUST_ID)
CONSTRAINT DEPTID_FK FOREIGNKEY (DEPT_ID)
REFERNCES DEPARTMENT(DEPTID) );
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EXPLANATION
DEPARTMENT :: Second Table which has DEPT_ID as PRIMARYKEY
CUSTOMER :: First Table which has CUST_ID as PRIMARY KEY
COMBINE :: The second example is used to establish the relation from the FIRST TABLE to SECOND TABLE using DEPT_ID attribute.Since DEPT_ID is the common attribute in both Tables.
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