bytes
tutorials
sql
difference between drop and truncate
Overview
"Drop" in SQL refers to the removal of a table or database from a server. "Truncate" is a SQL command that removes all rows from a table but keeps the table's structure intact. In this lesson, we will learn about how to Drop or Truncate and when the individuals are used.
What are Drop and Truncate?
Drop and Truncate are two common SQL statements utilized to erase information from a table. The DROP statement for all time erases the desired table and all the information stored in it. In contrast, the TRUNCATE statement expels all information from a table but does not erase the table itself. Both commands are effective once you remove a large number of records rapidly, but they have distinctive implications for the information stored within the table. The DROP command is more permanent and should be utilized cautiously, whereas the TRUNCATE command is more frequently utilized to reset a table to its empty state.
DROP
DROP is an SQL command utilized to erase an object such as a table, database, index, view, or stored procedure. It could be a DDL (Data Definition Language) statement that's utilized to remove a schema object from the database. DROP is utilized to remove a table or database from the database in conjunction with all its related information. DROP could be a permanent operation and cannot be fixed, so caution should be taken when utilizing the command.
Syntax
DROP TABLE table_name;
Example
DROP TABLE orders;
This command will delete the table called 'orders' from the database. All data stored within the table will be lost.
TRUNCATE
TRUNCATE could be a SQL statement that's utilized to erase all the records from a table in a database. It is distinctive from the Delete statement, which only erases the rows that match an indicated condition. TRUNCATE is commonly used when deleting huge amounts of information from a database table because it is faster and more effective than a Delete statement. TRUNCATE, too resets the table's identity column, in case any, back to its seed value.
Syntax
TRUNCATE TABLE table_name;
Example
TRUNCATE TABLE orders;
This statement will delete all the rows in the 'orders' table and reset the identity column, if any.
Difference between DROP and TRUNCATE
DROP | TRUNCATE |
---|---|
It completely removes a table from the database. | It deletes all the rows from the table. |
Rollback is not possible after deletion. | Rollback is possible after deletion. |
It is a DDL Command. | It is a DDL Command. |
It is slower than truncate. | It is faster than drop. |
It can be used with a where clause. | It can't be used with a where clause. |
It deletes indexes and triggers. | It doesn't delete indexes and triggers. |
Conclusion
This lesson clarifies the contrasts between the SQL commands "Drop" and "Truncate". "Drop" permanently erases a table or database and all stored information, whereas "Truncate" removes all information from a table but keeps the table structure intact. Both commands are useful for rapidly erasing expansive amounts of information, but "Drop" should be used cautiously because it may be a permanent operation.
Key takeaways
Quiz
1. What is the syntax to drop a database in SQL?
Answer: a. DROP DATABASE database_name;
2. What is the syntax to truncate a table in SQL?
Answer: a. TRUNCATE TABLE table_name;
3. What is the difference between DROP and TRUNCATE commands?
Answer: b. DROP deletes the table permanently while TRUNCATE only deletes the data.
4. What happens to the foreign key constraints when a table is truncated?
Answer: b. The foreign key constraints are maintained.