Do we need to drop index before dropping table?

Do we need to 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.

What happens to index when table is dropped in Oracle?

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).

Does drop table delete table 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.

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.

Does dropping table drop constraint Oracle?

Yes we can! Nothing remains. It's different when other objects reference the table.

Will dropping table drop trigger?

Normally you'd have a trigger on one table insert into your backup table (well, for one use of triggers). In that case, dropping the backup table would invalidate the trigger on the live table, but would not drop it. Only dropping the live table would drop the trigger on the live table.

Is TRUNCATE faster than DELETE?

TRUNCATE is a DDL(Data Definition Language) command. It is used to delete all the tuples from the table. Like the DROP command, the TRUNCATE command also does not contain a WHERE clause. The TRUNCATE command is faster than both the DROP and the DELETE command.

Which is faster TRUNCATE or DROP?

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 .

How to drop an index?

• The syntax of the DROP INDEX statement is simple as follows: DROP INDEX [schema_name.]index_name; First, specify an optional schema name to which the index belongs. If you omit the schema name, Oracle assumes that the index is in your own schema. Second, specify the name of the index that you want to remove.

How do I drop a table in SQL Server?

• Select the database from the left menu. Select a table from the list in the left menu or in the center box. Select Drop from the center row of the table you want to delete. Drop is SQL-speak for delete. Confirm in the popup box that appears.

What is DROP INDEX?

• DROP INDEX. Purpose. Use the DROP INDEX statement to remove an index or domain index from the database. When you drop an index, Oracle Database invalidates all objects that depend on the underlying table, including views, packages, package bodies, functions, and procedures.

How to drop index Oracle?

• To drop an index in Oracle SQL, you use the DROP command. It's a simple command and has only one option to change, which is the name of the index you wish to drop. So, to drop your index called idx_cust_fullname, your command would be: Your index will now be deleted from the database.