Frequent question: What is a drop table in SQL?

What does drop do in database?

Dropping a database deletes the database from an instance of SQL Server and deletes the physical disk files used by the database. If the database or any one of its files is offline when it is dropped, the disk files are not deleted. These files can be deleted manually by using Windows Explorer.

Is drop table the same as delete table?

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.

Does drop table delete the table?

The DROP TABLE is another DDL (Data Definition Language) operation. But it is not used for simply removing data from a table; it deletes the table structure from the database, along with any data stored in the table.

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.

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How do I DROP if a database exists?

The DROP DATABASE statement allows you to delete one or more databases with the following syntax:

  1. DROP DATABASE [ IF EXISTS ] database_name [,database_name2,… ];
  2. Cannot drop database “database_name” because it is currently in use. Code language: PHP (php)
  3. DROP DATABASE IF EXISTS TestDb;

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.

Is DELETE a DDL command?

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.

What is difference between DROP and DELETE?

DELETE is a Data Manipulation Language command, DML command and is used to remove tuples/records from a relation/table. Whereas DROP is a Data Definition Language, DDL command and is used to remove named elements of schema like relations/table, constraints or entire schema. … DELETE is DML.

What is difference between delete drop and truncate?

Objects deleted using DROP are permanently lost and it cannot be rolled back. Unlike TRUNCATE which only deletes the data of the tables, the DROP command deletes the data of the table as well as removes the entire schema/structure of the table from the database.

What will happen when the following statement is executed drop table table name?

It completely removes the table structure and associated indexes, statistics, permissions, triggers and constraints. You might have SQL Views and Stored procedures referencing to the SQL table. SQL Server does not remove these stored procedures and views.

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Can primary key be deleted?

You can delete (drop) a primary key in SQL Server by using SQL Server Management Studio or Transact-SQL. When the primary key is deleted, the corresponding index is deleted.

Can we drop a table with primary key?

The syntax to drop a primary key in SQL is: ALTER TABLE table_name DROP PRIMARY KEY; … The name of the table to modify. This is the table whose primary key you wish to drop.

Can we drop table having primary key?

If a primary key exists, it is dropped. The user need not drop the primary key before dropping the table. If the primary key of the table is referenced by a constraint belonging to another table, then the table is not dropped and an error is signaled.

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