mysql documentation

1. What is an index? Indexes are used to quickly search for records with specific values. All MySQL indexes are saved as B-trees. If no index exists, MySQL must scan all the records of the entire table from the first record until the required

Today, I encountered a strange problem. One column in the MySQL table is of the text type, and the where condition in a row of query statements is: Select * From tablename where columnname = 2; The result is incorrect. We can find the result at in

The example is as follows: When I used show InnoDB status to check the engine status, I found a deadlock problem: * ** (1) transaction: Transaction 0 677833455, active 0 sec, process no 11393, OS thread ID 278546 starting index read MySQL

You can set the value of the date. timezone key to 'Asia/Shanghai' in the urban configuration of the PHP script in PHP. ini. However, the shared VM itself does not have the permission to modify PHP. ini. At this time Program Add public part Ini_

I have completely completed the service today, but I do not have any official MySQL documentation. There are a lot of Apache and PHP, not to mention Linux. Therefore, Oracle is attracting more people to participate in their training in this way.

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The previous sections introduce relational algebra, relational design theory, and high-level concept representation. This section describes the SQL language. Currently, mainstream databases such as MySQL and Oracle only implement the SQL standard

An exception occurs when a newly developed website is opened every morning to access the database. The database is MySQL. That is to say, an exception occurs during a long idle period of time. The Exception Code is ** begin nested exception ** Com.

Field table and field naming Table field naming rules must be consistent with the names of variables mentioned above. content-related models should adopt the plural form, for example, dede_archives and dede_addonimages, which store fields of

When it comes to MySQL tuning, there are a lot of points that we can do, so combing, some tuning strategy, today just summarizes the tuning of server parametersActually speaking, the parameter tuning, my understanding is nothing more than two points:

1. Optimize your query for query cachingMost MySQL servers have query caching turned on. This is one of the most effective ways to improve sex, and this is handled by the MySQL database engine. When many of the same queries are executed multiple

MySQL optimization under 8G memory Try the following settings:Key_buffer = 3840MMax_allowed_packet = 16MTable_cache = 1024Sort_buffer_size = 32MRead_buffer_size = 32MRead_rnd_buffer_size = 32MMyisam_sort_buffer_size = 256MThread_cache_size =

Database operations are a major bottleneck in today's Web applications. Not only do DBAs (database administrators) need to worry about a variety of performance issues, but programmers are also trying to make accurate structured tables, optimize

Read the previous gr36_ predecessors in the Prophet on the topic, which refers to the sequencing injection, this has frequently encountered such problems in the recent, so first summarize the order by sequencing injection of knowledge.0x00

Today, database operations are increasingly becoming a performance bottleneck for the entire application, especially for Web applications. As for the performance of the database, this is not just something that DBAs need to worry about, and that's

When we design the database table structure, we need to pay attention to the performance of the data operation when we operate the database (especially the SQL statement when we check the table). Here, we don't talk too much about the optimization

Today, database operations are increasingly becoming a performance bottleneck for the entire application, especially for Web applications. As for the performance of the database, this is not just something that DBAs need to worry about, and that's

First, the origin of the problem There is a clear explanation in the official MySQL documentation that nested transactions are not supported: Copy Code code as follows: Transactions cannot be nested. This is a consequence of the

Databases are IO-intensive applications whose primary responsibility is data management and storage. And we know that the time to read a database from memory is a microsecond level, while reading an IO from a common hard disk is at a millisecond

By default, the 5.1.73 version is installed via Yum under CentOS 6.8, and now the requirement is to install the 5.7 version. MySQL official website: http://www.mysql.com MySQL Documentation: http://dev.mysql.com/doc/ ------------------------------