index used in database

Database index PrincipleWhen you encounter a new knowledge, you can learn it through the what-why-how method. Below we will learn the database index through this method.What is database index?Definition 1: an index is a structure used to sort the

Why create an index? This is because creating an index can greatly improve the system performance.First, you can create a unique index to ensure the uniqueness of each row of data in the database table.Second, it can greatly speed up data retrieval,

ReprintedBytes IndexYou can use indexes to quickly access specific information in database tables. An index is a structure that sorts the values of one or more columns in a database table (for example, the last name (lname) column of the employee

In the database, the index is a special object, it is a database structure that can speed up the data retrieval, it can quickly find the necessary content from the large amount of data, make the data query without retrieving the whole database. An

    I. Index Introduction 1.1 index creation Syntax: Create uniuqe | bitmap index . ON . (| ASC | DESC, | ASC | DESC ,...) TABLESPACE STORAGE LOGGING | NOLOGGING COMPUTE STATISTICS NOCOMPRESS | COMPRESS NOSORT | REVERSE PARTITION | global

Definition: An index is a structure that sorts the values of one or more columns in a database table and uses an index to quickly access specific information in a database table. For example such a query: SELECT * FROM table1 where id=10000. If

A Index Introduction1.1 Creation syntax of the index:CREATE UNIUQE | BITMAP INDEX .On .( | ASC | DESC, | ASC | DESC,...)Tablespace STORAGE LOGGING | NologgingCOMPUTE STATISTICSnocompress | CompressNosort | REVERSEPARTITION | GLOBAL

This article mainly originates from the Internet mainstream article, just according to the individual understanding slightly makes the integration, behind has the reference link. I. Summary This paper takes the MySQL database as the research object

This article is transferred from: Http://www.cnblogs.com/abcdwxc/archive/2007/12/11/990274.html ----------------------- Creates an index for a given table or view.Only the owner of a table or view can create an index for the table. The owner of a

0. ReferencesTable Scan, Index Scan, index SeekSQL Server–index Seek vs. Index Scan–diffefence and Usage–a simple NoteHow Oracle tables are accessedDifference between index seek and index scan and where applicableHow to access tables in 1.oracleIn