Create tables named Employee. Department, Salary, Implement all DDL commands on it.

 DDL (Data Defination Language):

1. CREATE TABLE

   It is used to create new table structure.
   syntax:CREATE TABLE table_name (column1,column2....);
   Create Table By Subquery.
   Syntax:CREATE TABLE table_name (column1,column2....) AS Subquery;

2. ALTER TABLE

   It is uaed to add, modify, or drop columns.
   syntax for ADD:ALTER TABLE table_name ADD (column datatype,column datatype....);
   syntax for MODIFY:ALTER TABLE table_name MODIFY (column datatype,column datatype....);
   syntax for DROP:ALTER TABLE table_name DROP (column);
   

3. DROP TABLE

   All data and structure of table is deleted.
   syntax:DROP TABLE table_name;
   

4. RENAME

   It is used to change the name of a table, view, sequence, or synonym.
   syntax:RENAME old_table_name TO new_table_name ;
   

5. TRUNCATE TABLE

   It is remove all rows from a table and releases the storage space used by that table. we can not roll back row removal using trancate.
   syntax:TRUNCATE TABLE table_name;
   

6. COMMENT

   It is used to add comments to a table or column by using the COMMENT statement.
   syntax:COMMENT ON TABLE table_name | COLUMN TABLE.column_name IS 'text';
   

For solving the above question we need to create two tables (EMPLOYEE , DEPARTMENT)

create table employee
(
empid number(5) primary key,
empname varchar2(50),
salary number(10,2),
Grade number(1),
deptno number(3) references department(deptno),
location varchar2(50),
desig varchar(20)
);

create table department
(
deptno number(3) primary key,
deptname varchar(50)
);

Then Insert few records in Employee and Department table.

EMPLOYEE

EMPID	EMPNAME	SALARY	GRADE	DEPTNO	LOCATION	DESIG
1	AMIT SEN	10000	1	1	BHOPAL	MANAGER
2	RAMESH THAKUR	11000	2	1	BHOPAL	CLERK
3	RAKESH	12000	1	1	INDORE	CLERK
4	SUMIT SAKET	9000	3	2	BHOPAL	CLERK
5	AMIT SEN	11000	2	2	BHOPAL	MANAGER
6	AMIT SEN	12000	2	5	INDORE	CLERK
7	AMIT SEN	15000	1	6	INDORE	MANAGER

DEPARTMENT

DEPTNO	DEPTNAME
1	SALES
2	PRODUCTION
3	PURCHASE
4	MARKETING
5	ACCOUNTS
6	HR
7	ADMIN