Truncate vs. Delete: What's the Difference?
Truncate removes all rows without logging individual row deletions; delete removes specific rows and logs them.
DELETE is a Data Manipulation Language (DML) command while TRUNCATE is a Data Definition Language (DDL) command.
TRUNCATE is much faster as compare to DELETE as it instantly erase the all data.
‘WHERE’ condition is required in DELETE. . If the ‘WHERE’ clause is omitted from the statement, all rows in the table are deleted. But we can’t specify ‘WHERE’ clause in a ‘TRUNCATE TABLE’ statement as it is all or nothing.
DELETE removes some or all rows from a table while TRUNCATE remove all rows.
DELETE causes all DELETE triggers on the table to fire while no triggers are fired on during TRUNCATE operation because it is not applicable on individual rows.
Delete can be used with indexed views while TRUNCATE can’t be uses with indexed views.
DELETE is executed using a row lock and each row in the table is locked for deletion while TRUNCATE is executed using a table lock and all table is locked for remove all records.
In the realm of database operations, both truncate and delete play pivotal roles in data management. Truncate is a swift operation that removes all rows from a table without logging each individual row deletion. It effectively resets a table, making it empty. Conversely, delete is a more meticulous process that removes specific rows based on conditions, logging each row deletion, which can be a slower operation.
Truncate, due to its nature of not logging individual row deletions, is faster and more efficient when the goal is to empty a table completely. However, this comes at the expense of not being able to specify conditions for deletions. Delete, while more resource-intensive, provides the flexibility to specify which rows to remove, using conditions in the WHERE clause of the SQL statement.
One noteworthy distinction is that truncate resets the identity column's seed value, if one exists in the table. If you were to insert new data post-truncation, the identity column would start from its seed value. Delete, in contrast, doesn't affect the identity column's current value. If you deleted certain rows and added new ones, the identity column would continue incrementing from its last assigned value.
In terms of transactions, truncate is a minimally logged operation, which means that only the deallocation of data pages is logged, not the individual rows. This makes it less suitable for scenarios where detailed transaction logs are crucial. Delete, given its row-by-row operation, creates more extensive logs, making it more apt for situations demanding detailed transaction records.
Slower due to logging
Doesn't log individual rows
Logs each deleted row
No conditions; removes all rows
Can specify conditions for row removal
Identity Column Impact
Resets seed value
Doesn't reset; continues from last value
Truncate and Delete Definitions
Truncate is a database operation.
It's advisable to back up data before a truncate.
Delete does not reset the identity column's value.
Post-delete, the identity column value remained unchanged.
Truncate doesn't log individual row deletions.
The log was concise after the truncate operation.
Delete operates on rows in a database table.
Using delete, they removed all entries from the year 2015.
Truncate resets a table's identity column seed.
After the truncate, the first new entry was numbered '1'.
Delete is a more resource-intensive operation.
They avoided using delete during peak hours due to its demand on resources.
Truncate removes all rows from a table.
To quickly clear the table, he chose to truncate it.
Delete logs each individual row deletion.
The extensive log captured every detail from the delete operation.
Truncate is a minimally logged operation.
Given the absence of row details, the truncate kept the log ligh
Delete removes specific rows based on conditions.
To remove outdated records, he used a delete command.
To shorten or reduce
The script was truncated to leave time for commercials.
To cancel, strike out, or make impossible to be perceived
Deleted the expletives from the transcript with a marker.
To shorten (a number) by dropping one or more digits after the decimal point.
Can truncate be used to remove specific rows?
No, truncate removes all rows without conditions.
Are both truncate and delete reversible?
If within a transaction and not committed, yes. However, post-commit, a backup would be required.
What does truncate do in a database?
Truncate swiftly removes all rows from a table without logging each row's deletion.
What happens to a table's identity column after truncation?
It resets to its seed value.
Why might delete be preferred despite being slower?
For its flexibility to specify which rows to remove and for detailed logging.
Does truncating a table remove its structure?
No, it only removes the data, not the table's schema.
Which operation is safer for crucial data?
Delete, as it allows for more specific conditions and detailed logging.
Can both operations be used in all databases?
While widely supported, there might be specific implementations or restrictions in certain databases.
Can you truncate a table with foreign key constraints?
Typically, no; constraints can prevent truncation.
Is it possible to rollback after a delete or truncate?
If executed within a transaction and not committed, yes. Otherwise, recovery from backups is necessary.
Which operation requires more system resources?
Delete, particularly for large datasets, due to its row-by-row operation.
Is delete a faster operation than truncate?
No, delete is generally slower due to its logging of individual rows.
Why might one use truncate over delete?
For a quicker, less logged operation to entirely clear a table.
How does delete differ from truncate?
Delete removes specific rows based on conditions and logs each row, while truncate clears all rows without detailed logging.
Do both operations free up space in the database?
Yes, but the space might not be immediately released to the operating system.
In terms of data integrity, which is more reliable?
Delete, given its detailed logging and ability to specify conditions.
Can delete affect a table's identity column?
No, delete doesn't reset the identity column's current value.
Which operation is more log-intensive?
Delete, as it logs every row's deletion.
What should be done before truncating a table?
Backup the data if it's valuable, as truncation is swift and thorough.
Can I use a WHERE clause with truncate?
No, truncate doesn't support conditions.
Written bySumera Saeed
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Edited byHuma Saeed
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