Does dropping a table delete the data?
DROP will delete all data and the table structure as well. DELETE will delete the data but the table structure will remain the same and we can still rollback the data. Also with DELETE you can use the where condition i.e. to delete only certain records.
What does the drop table statement do?
SQL DROP TABLE statement is used to remove table in a database. When you use the SQL DROP TABLE statement to remove a table, the database engine deletes all objects associated to that table including data, table structure, indexes, constraints, triggers and maybe privileges.
Does Drop table delete Index?
DROP TABLE always removes any indexes, rules, triggers, and constraints that exist for the target table. However, to drop a table that is referenced by a view or a foreign-key constraint of another table, CASCADE must be specified.
Which is better TRUNCATE or DELETE?
Truncate removes all records and doesn’t fire triggers. Truncate is faster compared to delete as it makes less use of the transaction log. Truncate is not possible when a table is referenced by a Foreign Key or tables are used in replication or with indexed views.
Which is faster TRUNCATE or DROP?
TRUNCATE is a DDL(Data Definition Language) command. It is used to delete all the tuples from the table. … The TRUNCATE command is faster than both the DROP and the DELETE command. Like the DROP command we also can’t rollback the data after using the this command.
Can we DROP a table or column which has primary key?
We can remove PRIMARY KEY constraint from a column of an existing table by using DROP keyword along with ALTER TABLE statement.
How many joining conditions are needed to join 10 tables?
relations are possible between 10 tables, but this is just considering relations between tables (not based on different columns between tables) as it will make that number much bigger. If we make the restriction that each table may appear at most once, there are 2^10-1 = 1023 possibilities.
How do you destroy a table in SQL?
Using SQL Server Management Studio
- In Object Explorer, select the table you want to delete.
- Right-click the table and choose Delete from the shortcut menu.
- A message box prompts you to confirm the deletion. Click Yes. Deleting a table automatically removes any relationships to it.
Should I DROP index before dropping table?
3 Answers. Yes, it does. However, if you have foreign key constraints such as RESTRICT that ensure referential integrity with other tables, you’ll want to drop those keys prior to dropping or truncating a table. Yes it would drop the index.
Is DELETE DDL or DML?
DROP and TRUNCATE are DDL commands, whereas DELETE is a DML command. DELETE operations can be rolled back (undone), while DROP and TRUNCATE operations cannot be rolled back.
Does DROP table free up space?
Dropping a table will free up the space within the database, but will not release the space back to Windows. That requires shrinking the database file.
Why is TRUNCATE faster than delete?
TRUNCATE is faster than DELETE , as it doesn’t scan every record before removing it. TRUNCATE TABLE locks the whole table to remove data from a table; thus, this command also uses less transaction space than DELETE . Unlike DELETE , TRUNCATE does not return the number of rows deleted from the table.
Does TRUNCATE free space?
Truncating a table does not give any free space back to the disk – you need to run a SHRINKDATABASE operation for the allocated space to be successfully de-allocated and returned to the disk. Also, as others have mentioned, maybe the table was not taking up much space in the first place.