key order

Original: MySQL primary key design[TOC]In the process of the project encountered a seemingly very basic problem, but in-depth thinking has led to a lot of problems, I think it is necessary to take this learning process to record.MySQL primary key

There are many ways to SQL optimization, and today it's about database indexing.To illustrate:Suppose there is a book table with Fields Id,name, ISBN and so on. If the number of books is large, we usually use the ISBN query is relatively slow.To add

Write in front: indexes have a critical impact on the speed of queries, and understanding indexes is also a starting point for database Performance tuning. Consider the following scenario, assuming that a table in the database has 10^6 records, the

Proofing rules: The order of comparisons between characters under the current encoding. (CS case sensitive, CI case insensitive, bin binary code comparison)1. View current proofing rules show collation;Each character set supports an indefinite

In the process of using MySQL, you may encounter a similar problem:[email protected] 07:42:00>select * FROM test where C1 like ' ab% ';+-----+| C1 |+-----+| ABC || ABD |+-----+Fuzzy matching ab%, the result of a string beginning with AB also appears

In the process of using MySQL, you may encounter a similar problem:[email protected] 07:42:00>select * FROM test where C1 like 'ab%';+-----+| C1 |+-----+| ABC || ABD |+-----+Fuzzy matching ab%, the result of a string beginning with AB also appears

There are many database optimization can be said, according to the amount of data supported can be divided into two stages: single-machine database and sub-Library sub-table, the former can generally support 500W or 10G of data, more than this value

--The query field in what tableSelect * from where t.column_name='ABC';--Query What table the field is in and determine if it is a primary keySelect * fromAll_tab_cols T Left Join ( SelectA.table_name, A.constraint_name,

recently, as requested by the team, the study collated the following MySQL-related optimizations, some of which are based on actual Java projects encountered in the context of experience. Welcome to the discussion ~The SQL language is a powerful and

Indexes are the basis of efficient use of the database, but when your data volume is very small, perhaps by scanning the whole table to access the performance of the data is acceptable, but when the amount of data is very large, when the traffic is

Write in front: indexes have a critical impact on the speed of queries, and understanding indexes is also a starting point for database Performance tuning. Consider the following scenario, assuming that a table in the database has 10^6 records, the

------------------------Create an advanced junction-------------------------58. Using Table/Column aliases--58.1. Using aliases on tablesSELECT Cust_name,cust_contactFrom customers as c,orders as o,orderitems as OiWHERE c.cust_id =o.cust_idand

Http://www.cnblogs.com/xrq730/p/4937222.htmlObjectiveThe database storage engine is the database's underlying software organization, and the Database management system (DBMS) uses the data engine to create, query, update, and delete data. Different

The Oracle database object is also called the schema object, and the database object is a collection of logical structures, and the most basic database object is a table. Other database objects include: Synonyms synonyms are an alias for an existing

Category: LinuxAn overview of the INSERT processing processFirst, let's take a quick look at the processing steps when inserting a row. Each of these steps has the potential for optimization, which we'll discuss in a later step.Prepares the

Write in front: indexes have a critical impact on the speed of queries, and understanding indexes is also a starting point for database Performance tuning. Consider the following scenario, assuming that a table in the database has 10^6 records, the

The selection of DB2 performance optimization policies determines the effect of database optimization. The following describes the considerations for optimizing the performance of ten DB2 databases. I hope this will help you learn about the

Original article: StairwaytoSQLServerIndexes: Level2, DeeperintoNonclusteredIndexes this article is part of the advanced series of SQL Server indexes (StairwaytoSQLServerIndexes. In Level 1 Original article: StairwaytoSQLServerIndexes: Level2,

This article is mainly translated from the cassandra1.2 document of Datastax. Objective: To reduce the number of sstables and Merge multiple sstables in the sequence of IOSStable: compression: In Cassandra, write new columns into the new sstable,

On the list page, the programmer used the "Wuqi. Webdiyer" Paging plug-in, which was slow and could not be found. After reading the code, I thought there was too much redundancy, so I decided to optimize it. On the list page, the programmer used the