TCL Commandss
TCL stands for Transaction Control Languages. These commands are used for maintaining consistency of the database and for the management of transactions made by the DML commands.
- COMMIT
- ROLLBACK
- SAVEPOINT
Aptitude
- Introduction
- File System vs DBMS
- Tuple
- Record
- Architecture
- Need of DBMS
- DBMS Abstraciton and Indipendence
- Data Models
- ER Models
- RDBMS
- Relational Data Model
- SQL Introduction
- SQL Types
- DDL Commands
- DQL Commands
- DML Commands
- DCL Commands
- TCL Commands
- Default Constraints
- Check Constraint
- Not Null Constraint
- Unique Constraint
- Key Constraint
- Key In DBMS
- Primary Key
- Foreign Key
- Super Key
- Candidate Key
- Alternate Key
- Composite Key
ER Models
RDBMS
SQL
SQL Constraints
Keys In DBMS
SQL TCL Commands
TCL Commands
A Transaction is a set of SQL statements that are executed on the data stored in DBMS. Whenever any transaction is made these transactions are temporarily happen in database.So to make the changes permanent, we use TCL commands.
1.COMMIT
This command is used to save the data permanently. Whenever we perform any of the DDL command like -INSERT, DELETE or UPDATE, these can be rollback if the data is not stored permanently. So in order to be at the safer side COMMIT command is used.
Syntax
COMMIT;
2.ROLLBACK
This command is used to get the data or restore the data to the last savepoint or last committed state. If due to some reasons the data inserted, deleted or updated is not correct, you can rollback the data to a particular savepoint or if savepoint is not done, then to the last committed state.
Syntax
ROLLBACK;
2.SAVEPOINT
This command is used to save the data at a particular point temporarily, so that whenever needed can be rollback to that particular point.
Syntax
UPDATE NAME
SET NAME= ‘Rossie’
WHERE marks= 70;
SAVEPOINT A;
INSERT INTO STUDENT
VALUES (‘Zack’, 76);
Savepoint B;
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