A DIFFERENCE BETWEEN DELETE AND TRUNCATE IN SQL

Computer Engineering

While working with the database we often need to delete data, sometimes to create more space, sometimes just remove all data to make table ready for next day's transaction or sometimes just selectively remove stale data. SQL provides a couple of handy commands to remove data e.g. truncate, delete and drop. The last one is bit different because instead of removing data it just deletes table. What is the difference between truncate and delete command in SQL or when to use truncate vs delete is one of the most frequently asked SQL interview question? Knowledge of this critical command is not only useful for interviews, but also while working with a big database with a large number of records, especially while writing SQL scripts for purging transaction databases. An Incorrect choice of SQL command can result is either very slow processor can even blow up the log segment; if too much data needs to be removed and log segment is not enough. That's why it's critical to know when to use truncate and delete command in SQL. In this paper, we will first see few differences between them, and based upon them, you should be able to find out when DELETE is a better option for removing data or TRUNCATE should be used to purge tables.

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