An index is a
physical structure containing pointers to the data. Indices are created in an
existing table to locate rows more quickly and efficiently. It is possible to
create an index on one or more columns of a table, and each index is given a
name. The users cannot see the indexes; they are just used to speed up queries.
Effective indexes are one of the best ways to improve performance in a database
application. A table scan happens when there is no index available to help a
query. In a table scan, the SQL Server examines every row in the table to
satisfy the query results. Table scans are sometimes unavoidable, but on large
tables, scans have a terrific impact on performance.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment