PRACTICAL NUMBER_1
➤Create tables named employee, department, Salary, Implement all DDL commands on it.
DDL (Data Definition Language) Commands are-
- Create,
- Alter table (to Add Column, to Modify Column and to DROP Column)
- Rename
- Truncate
- Drop
1. Create table Command-->
SQL> connect ⤶
Enter user-name: system⤶
Enter password : password⤶
connected
SQL>Create table Employee ( Emp_Id int primary key, Name varchar(20) , age int, city varchar(30));⤶
Table Created.
SQL> Create table Department( DeptId int primary key, Dept_Name varchar(20));⤶
Table Created.
SQL> Create table Salary ( Emp_Id int, Salary numeric(10,2));⤶
Table Created.
DDL Commands-Create Table |
2. (a) Alter Table Command to Add Column--> we use this command to add Mobile Column in Employee Table.
SQL> Alter table Employee ADD Mobile number(10);⤶
Table altered.
2. (b) Alter table Command to Modify Column--> we use this command to modify Name Column with Not Null Constraint.
SQL> Alter table Employee MODIFY Name varchar(20) not null;⤶
Table altered.
2. (c) Alter table Command to DROP Column--> we use this command to drop or destroy Name Column.
SQL> Alter table Employee DROP COLUMN Name;⤶
Table altered.
DDL Commands-Alter Table(Add Column, Modify Column or Drop Column) |
3. Rename Command--> this command is used to Rename object and here we will rename Employee table name to Employee_Record.
SQL>rename Employee to Employee_Record;⤶
Table renamed.
4. TRUNCATE Command--> this command is used to delete data permanently.
SQL>TRUNCATE Table Employee_Record;⤶
Table truncated.
5. DROP Command--> this command is used to drop table, view, user, sequence, synonym etc.
SQL>drop table Employee_Record;⤶
Table dropped.
DDL Commands- Rename, Truncate, Drop |
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