Index operations

An index is a database structure created for a table to sort data in one or more columns of the table in a specific order. It mainly improves the query speed and reduces the performance overhead of database systems.

Create an index

Use the CREATE INDEX statement to create a table index.

Example:

1. Run the following command to create Table test:

   obclient> CREATE TABLE test (c1 int primary key, c2 VARCHAR(10));
   

2. Run the following command to create an index for Table test:

   obclient> CREATE INDEX test_index ON test (c1, c2);
   

   For more information about the CREATE INDEX statement, see "CREATE INDEX".

View an index

Use the SHOW INDEX statement to view the index of a table.

Example:

View the index of Table test.

obclient> SHOW INDEX FROM test;

Delete an index

Use the DROP INDEX statement to delete the index of a table.

Example:

Delete the index of Table test.

obclient> DROP INDEX test_index ON test;

For more information about the DROP INDEX statement, see "DROP INDEX".