index key

Btree and Hash Hash index structure of the particularity, its retrieval efficiency is very high, index retrieval can be located at once, unlike B-tree index need from the root node to the side point, and finally access to the page node so many IO

Include column indexOverviewThe include column index is also a nonclustered index, and the index structure is the same as the clustered index structure, where the non-key column containing the column index is stored only on the leaf node, the

Original: SQL Server index and table Architecture (III)Include column indexOverviewThe include column index is also a nonclustered index, and the index structure is the same as the clustered index structure, where the non-key column containing the

Original: SQL Server index and table architecture (including column index)Include column indexOverviewThe include column index is also a nonclustered index, and the index structure is the same as the clustered index structure, where the non-key

1, problem descriptionHow does a SQL work in a database? I believe a lot of people will be interested in this problem. Of course, to fully describe a SQL in the database life cycle, this is a very big problem, covering the SQL lexical parsing,

How does SQLSERVER locate the target data through indexing and Statistics (article 2) before reading the content of this article, please read the content of the first article first, without the foundation of the first article, we will see the first

Mysql index Overview An index is essentially a type of table. This type of table stores the column values listed as indexes and pointers pointing to real complete records. The index is transparent to users and is only used by the database engine to

A brief introduction to Sybase database Sybase Company was founded in 1984, the company name "Sybase" from "System" and "database" combined meaning. Sybase's first relational database product was the Sybase SQLServer1.0, which was launched in May 19

This article is part of the "Stairway series: Steps for SQL Server Indexing"Indexes are the basis of database design and tell developers to use the database with regard to the designer's intentions. Unfortunately, when performance problems arise,

MySQL currently has the following types of indexes: Normal index allows the same indexed content to appear (normal) Unique indexes unique can not appear the same value, can have a null value Primary key index Promary key

1. Table and index storage structureBefore SQL Server2005, a table was stored in a B-tree or a heap. Each B-tree or heap has a record corresponding to the sysindexes. After SQL Server2005, introduced the concept of partitioned tables (table

1 indexes in SQL Server　　An index is an on-disk structure associated with a table or view, which speeds up the retrieval of rows from a table or view. An index contains keys that are generated by one or more columns in a table or view. These keys

Reference Original: http://www.cnblogs.com/tjy9999/p/4494662.html1. Nonclustered indexesSET STATISTICSIo on SET STATISTICSTime on --1. No index (logical reads 568)SELECTFirstName, LastName fromDbo. ContactWHERELastName like 's%' --To create a

Reprinted please indicate the source: http://write.blog.csdn.net/postedit/40589651 The B-tree index in the Oracle database is like an inverted-long tree, which contains two types of data blocks: one is the index branch block, the other is that the

Understand the internal structure of B * tree index and the internal structure of tree Reprinted please indicate the source: http://write.blog.csdn.net/postedit/40589651 The B-tree index in the Oracle database is like an inverted-long tree, which

An index is essentially a type of table. This type of table stores the column values listed as indexes and pointers pointing to real complete records. The index is transparent to users and is only used by the database engine to accelerate the

A clustered index in which the data is actually stored sequentially, and the data page is on the index page. It's like a reference manual that all the topics are organized in order. Once you have found the data you want to search, you complete this

Objective In order to ensure consistent integrity of data, there is a locking mechanism in any database. The quality of locking mechanism should be directly thought of the concurrent processing ability and performance of a database system, so the

The MySQL order BY keyword is used to classify the data in the record. MySQL ORDER BY keyword classified by keyword The ORDER BY keyword is used to classify the data in a record. MySQL ORDER BY syntax The code is as follows Copy

Each storage engine uses three types of locking mechanisms: row-level locking, table-level lock page-level locking. Table-level locking is mainly MyISAM, memory, CSV and other non-transactional storage engines, using row-level locking is mainly the