SQL Why Table Indexes

Where, What and Why Index?

  • In a relational database management system, an index is a mechanism for boosting performance.
  • This is true for the selecting of data from tables, but not for the updates, it may be slow down the performance.
  • Create a unique index on the column or columns included in the PRIMARY KEY of a table as the PRIMARY KEY is often used in connection with other tables.
  • A column that appears often in sorted order should be indexed so that the system can take advantage of an indexed sort.
  • Columns that are regularly used in joins should be indexed because the database management system performs the join faster.
  • Columns, which is used to search for upper or lower limits can be a good choice for indexing.
© 2010 by Finnesand Data. All rights reserved.
This site aims to provide FREE programming training and technics.
Finnesand Data as site owner gives no warranty for the correctness in the pages or source codes.
The risk of using this web-site pages or any program codes from this website is entirely at the individual user.