Can We Drop A Table That Has Dependent Views On It?

What does it mean to drop a table?

The drop table command is used to delete a table and all rows in the table.

Deleting all of the records in the table leaves the table including column and constraint information.

Dropping the table removes the table definition as well as all of its rows..

Can primary key be deleted?

No, you cannot delete the primary key from one table without removing all the dependencies that other tables have on that key. Even if you try to do that, an error will be raised which will not let you do so.

Does Drop Table remove constraints?

DROP TABLE removes tables from the database. … 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.

Is commit required after drop table in Oracle?

CREATE TABLE and DROP TABLE statements do not commit a transaction if the TEMPORARY keyword is used. … SELECT causes an implicit commit before and after the statement is executed when you are creating nontemporary tables. (No commit occurs for CREATE TEMPORARY TABLE … SELECT .)

What happens to view when table is dropped?

Dropping a table removes the table definition from the data dictionary. All rows of the table are no longer accessible. All indexes and triggers associated with a table are dropped. All views and PL/SQL program units dependent on a dropped table remain, yet become invalid (not usable).

Can we drop a table 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.

Can we delete parent table without deleting child table?

You can’t drop a parent table if you have a child table with a foreign key constraint in place, unless you specify the CASCADE CONSTRAINTS clause: DROP TABLE P CASCADE CONSTRAINTS; This command drops the FK constraint too. Deleting a table will necessarily drop all constraints related to this table.

Can we drop a column with data in Oracle?

Oracle 8i introduced the ability to drop a column from a table. Prior to this it was necessary to drop the entire table and rebuild it. Now you can mark a column as unused (logical delete) or delete it completely (physical delete).

Can a view be updated?

The SQL UPDATE VIEW command can be used to modify the data of a view. All views are not updatable. So, UPDATE command is not applicable to all views. An updatable view is one which allows performing a UPDATE command on itself without affecting any other table.

When you drop a table all its trigger objects are deleted with it?

Dropping a table invalidates dependent objects and removes object privileges on the table. If you want to re-create the table, then you must regrant object privileges on the table, re-create the indexes, integrity constraints, and triggers for the table, and respecify its storage parameters.

When a table is dropped from database the view based on that table is also dropped?

If a VIEW, by definition of a view, is a subset of that which is in the database (whether on one or more tables), then if you drop even one of those tables then then VIEW becomes invalid. Therefore according to database logic such a View cannot exist. (All the data in that table is ‘destroyed’ on dropping).

What happens if we remove primary key from SQL table?

You can delete (drop) a primary key in SQL Server 2019 (15. x) by using SQL Server Management Studio or Transact-SQL. When the primary key is deleted, the corresponding index is deleted.

How do I recover a dropped table in Oracle without flashback?

RMAN – You can recover a single dropped table by restoring the entire database into your test environment using RMAN, and then roll forward. You can then extract the table and copy it from test to production using CTAS over a database link and then re-add the indexes and constraints.

What are dropped automatically when table dropped?

By default, MS Sql Server also drops indexes when a table is dropped.

What happens when you drop a table in SQL?

We use the SQL DROP Table command to drop a table from the database. 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.

How can you tell who dropped a table in SQL Server?

Now the challenge is how to find out who dropped the table which was created in the database. There is a simpler way to do the same. First right click on the database – Go to Reports >> Standard Reports >> Schema Changes History.

Why drop table if exists?

The DROP TABLE SQL statement enables you to delete a table from the database. If the table did not exist then attempting to DROP it would cause an error to occur. The DROP TABLE IF EXISTS SQL statement enables a check to see that the table exists prior to attempting the dropping (deletion) of the table.

Does drop table free up space Oracle?

Unless you specify the PURGE clause, the DROP TABLE statement does not result in space being released back to the tablespace for use by other objects, and the space continues to count toward the user’s space quota. For an external table, this statement removes only the table metadata in the database.