SQL TRUNCATE TABLE is a command used in Structured Query Language (SQL) to delete all the data from a table in a database. The TRUNCATE TABLE statement is a data manipulation language (DML) command that can be used to remove all the data from a table quickly and efficiently.
When you use the TRUNCATE TABLE command, all the rows in the specified table are deleted, and the table structure remains intact. This command is often used when you need to remove all the data from a table but want to keep the table structure and metadata, such as indexes, triggers, and constraints.
The syntax for the TRUNCATE TABLE command is straightforward. Here is an example:
TRUNCATE TABLE table_name;
In this syntax, table_name is the name of the table you want to truncate. You can also truncate multiple tables at once by separating the table names with commas, like this:
TRUNCATE TABLE table1, table2, table3;
It’s important to note that the TRUNCATE TABLE command is a DDL (data definition language) statement, not a DML statement. This means that it is used to modify the structure of the database, not the data within it. Because of this, the TRUNCATE TABLE command is a faster and more efficient way to delete data than using a DELETE statement, which is a DML statement.
One potential drawback of the TRUNCATE TABLE command is that it cannot be rolled back, meaning that once you truncate a table, you cannot undo the action. Additionally, if the table has any foreign key constraints, you may need to disable or drop them before truncating the table.
In summary, the TRUNCATE TABLE command in SQL is a powerful tool that allows you to quickly and efficiently delete all the data from a table in a database while preserving the table’s structure and metadata. However, it is important to use this command with caution and ensure that it is the appropriate action for your database needs.