MySQL index details, MySQL index detailsI. Introduction to index basics 1.1
In MySQL, indexes are also called keys. They are a data structure that the storage engine uses to quickly find records.
Indexes are critical to good performance. Especially
1. Display the list of databasesshow databases; # View all current databasesShow Databases \g #以行的方式显示2. On the command line, execute the SQL statementMysql-e ' show databases '-uroot-p123456mysqlshow-uroot-p123456 # not used, just remember the one
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Excerpt from http://book.51cto.com/art/200906/132406.htm
the pros and cons of 8.4.5 indexes and how to determine whether an index is needed
I believe readers know that indexing can greatly
SYS. dm_exec_requests is a powerful tool to check the performance bottleneck of SQL Server.
Update statistics t_goods with fullscan --- Update table statisticsThe index leaves of clustered indexes are the data itself.The leaf node of the
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
Creating an index is the establishment of an index on one or more columns of a table to increase the speed of access to the table. There are 3 ways to create an index, the 3 ways to create an index when creating a table, to create an index on a
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
The main considerations for designing SQL Server indexes are as follows:Check where condition and join condition column;Use narrow index;Check the selectivity of the column;Check the data type of the column;Consider the order of the columns;Consider
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