Database Reference
In-Depth Information
its growing rate. Moreover, you would not be using them all in
your search criteria.
Example:
CREATE INDEX emp_test_idx
ON emp_tests (empno);
Where emp_test_idx is the name that we have given to this index
and its created on empno column of emp_test table.
Example:
CREATE INDEX m1_idx
ON m1 (id1, id2);
Where m1_idx is the name of the index, which is created on two
columns id1, and id2 of m1 table. Such type of index is called
composite index as they gets created on two or more than two
columns.
Example:
ALTER INDEX m1_idx RENAME TO m2_idx;
This statement will rename the index to m2_idx.
Example:
DROP INDEX m2_idx;
This statement will drop the index on that particular column all
together.
Sequence is also a logical structure in the database. Just like
tables and views, they are also called as objects. Basically
Sequence generates sequence number so you do not have to
remember what id number we should give to newly hired
employee. Just ask the sequence for next value and it provide
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