TRUNCATE - ( Oracle Misc )

In Oracle, TRUNCATE is a command used to remove all rows from a table in a faster way than using the DELETE statement. It removes all data from a table and resets the high-water mark of the table.

Syntax

The syntax for using the TRUNCATE command in Oracle is as follows:

TRUNCATE TABLE table_name;

Here, table_name is the name of the table from which you want to remove all rows.

Example

Consider a table called employees with columns id, name, and salary. To remove all the rows from this table using TRUNCATE, we can use the following SQL command:

TRUNCATE TABLE employees;

Output

After executing the TRUNCATE command, all the rows in the employees table are deleted, and the table is empty.

Explanation

In the above example, we have used the TRUNCATE command to remove all the rows from the employees table in an efficient way. The TRUNCATE command is much faster than using the DELETE command because it deallocates space used by the table and resets the high-water mark.

Use

The TRUNCATE command is useful when you need to remove all rows from a table quickly and efficiently, without removing the table structure. It is particularly helpful when performing large-scale data manipulations, especially in data warehousing and reporting environments.

Important Points

• TRUNCATE is used to remove all rows from a table in Oracle.
• It is faster and more efficient than using the DELETE statement.
• The TRUNCATE command deallocates space used by the table and resets the high-water mark.
• It is useful for large-scale data manipulations, especially in data warehousing and reporting environments.

Summary

In summary, TRUNCATE is a command used to remove all rows from a table in Oracle. It is faster and more efficient than using the DELETE statement because it deallocates space used by the table and resets the high-water mark. The TRUNCATE command is particularly useful for large-scale data manipulations in data warehousing and reporting environments.