Question: What Is The Difference Between Drop And Truncate Commands?

Can we rollback truncate?

You cannot ROLLBACK TRUNCATE Simply, you cannot rollback a transaction if it is already committed but you can do something else to get the data back (or at least some parts of it).

When you execute the TRUNCATE statement, your data is still in the MDF file..

Why truncate is DDL?

TRUNCATE resets the high water mark of the table, effectively eliminating all the previously existing rows. Treating it as a DDL statement allows it to be super-fast, as it allows it to function without retaining undo (rollback) information like DML statements.

What is difference between truncate drop and delete explain with example?

The DROP command removes a table from the database. All the tables’ rows, indexes, and privileges will also be removed. … DROP and TRUNCATE are DDL commands, whereas DELETE is a DML command. DELETE operations can be rolled back (undone), while DROP and TRUNCATE operations cannot be rolled back.

What is the use of drop command?

DROP is used to delete a whole database or just a table. The DROP statement destroys the objects like an existing database, table, index, or view. A DROP statement in SQL removes a component from a relational database management system (RDBMS).

Why use truncate instead of delete?

TRUNCATE is faster than DELETE , as it doesn’t scan every record before removing it. TRUNCATE TABLE locks the whole table to remove data from a table; thus, this command also uses less transaction space than DELETE . Unlike DELETE , TRUNCATE does not return the number of rows deleted from the table.

What is difference between drop and delete?

DELETE is a Data Manipulation Language command, DML command and is used to remove tuples/records from a relation/table. Whereas DROP is a Data Definition Language, DDL command and is used to remove named elements of schema like relations/table, constraints or entire schema. … DELETE is DML. DROP is DDL.

Is Grant DDL or DML?

Data definition language (DDL) statements let you to perform these tasks: Create, alter, and drop schema objects. Grant and revoke privileges and roles. Analyze information on a table, index, or cluster.

What is the difference between drop and delete in mysql?

Delete is used to remove the rows, while drop is used to remove the tables and DB. delete – removes the rows from the table – where clause can be used to delete specific rows. … drop – removes a table from the database. – rows, indexes and privileges will also be removed.

Which is faster truncate or drop?

TRUNCATE is a DDL(Data Definition Language) command. It is used to delete all the tuples from the table. Like the DROP command, the TRUNCATE command also does not contain a WHERE clause. The TRUNCATE command is faster than both the DROP and the DELETE command.

Why drop table if exists?

The DROP TABLE SQL statement enables you to delete a table from the database. If the table did not exist then attempting to DROP it would cause an error to occur. The DROP TABLE IF EXISTS SQL statement enables a check to see that the table exists prior to attempting the dropping (deletion) of the table.

What are the DML commands?

Some commands of DML are:SELECT – retrieve data from the a database.INSERT – insert data into a table.UPDATE – updates existing data within a table.DELETE – deletes all records from a table, the space for the records remain.MERGE – UPSERT operation (insert or update)CALL – call a PL/SQL or Java subprogram.More items…•