Index in sql | Drop index in sql - sql - sql tutorial - learn sql
- 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.
- Removes one or more relational, spatial, filtered, or XML indexes from the current database.
- You can drop a clustered index and move the resulting table to another filegroup or partition scheme in a single transaction by specifying the MOVE TO option.
- The DROP INDEX statement does not apply to indexes created by defining PRIMARY KEY or UNIQUE constraints.
- To remove the constraint and corresponding index, use ALTER TABLE with the DROP CONSTRAINT clause.
- Sometimes we may decide that a particular index is no longer needed for a table.
- In those cases, that index should be removed to free up storage.
- To drop an index in SQL, we specify that we want to change the table structure via the ALTER TABLE command, followed by the DROP INDEX command.
- The SQL syntax to drop an index from a table is,
- Let's look at the example. Assuming our starting point is the Customer table created in the CREATE TABLE section:
Table Wikitechy Customer
|Column Name||Data Type|
- Assume we want to drop the index created in the ALTER TABLE ADD INDEX section. To do this, we type in the following:
- Please note that using ALTER TABLE to drop an index in supported in MySQL but not in Oracle or SQL Server.
- -- Syntax for SQL Server (All options except filegroup and file stream apply to Azure SQL Database.)
- Syntax for Azure SQL Database
- Syntax for Azure SQL Data Warehouse and Parallel Data Warehouse