When it comes to deleting data from a database, there are two main commands that are used: delete and truncate. While both of these commands can be used to remove data from a table, they have some key differences that make them better suited for different tasks. In this article, we'll explore the differences between delete and truncate, and when each should be used. The delete command is used to remove specific rows from a table.
It can be used to delete all rows or just a subset of rows. This command is slower than the truncate command, as it records the entries for each row removed from the transaction log. Additionally, delete can be used to delete records from tables and tables within a cluster. The truncate command is used to remove all rows from a table or an entire cluster.
It is faster than delete as it does not record the entries for each row removed from the transaction log. A table-level lock will be added when truncating. Truncate also removes all rows from a table, so it does not use as much undo space as delete. It's important to note that truncate transactions can be undone in database engines such as SQL Server and PostgreSQL, but not in MySQL and Oracle.
Additionally, truncate can be used to remove all data from the table without maintaining the integrity of the table, while delete can only be used to delete specific data and must comply with integrity compliance mechanisms. When deciding which command to use, it's important to consider the task at hand. If you want to quickly delete all the rows in a table, and you're sure you want to do it, and you don't have foreign keys in the tables, then truncate will be faster than delete. However, if you need to delete specific records or maintain the integrity of the table, then delete is the better option.
In short, when it comes to deleting data from a database, it's important to understand the differences between delete and truncate and when each should be used. Delete is slower but allows for more control over which records are deleted, while truncate is faster but cannot be undone and does not allow for any filtering of records.