about mysql

Mysql Author: Wang Mei (HeartIcy@163.com) The loss of the password is very distressing things, especially the root password lost: (. Install yourselfPlay lost also lost, but in the event of a production server hanging trouble can be big! Now

mysql> SET foreign_key_checks = 0; Query OK, 0 rows affected (0.02 sec) mysql> Delete from repositories where repo_name = "watch/sinawatch_agent_update"; Q Uery OK, 1 row affected (0.02 sec) mysql> SET foreign_key_checks = 1; Query OK, 0 rows

Recently has been plagued by the work of MySQL join problem, the company does not recommend the use of multi-table query, so I explore how join is workingThe answer is NO!CollectionIn other words, the table query says that the field of order by

From "Find" to B + Tree The index is used to find. Binary is a great way to find. Suitable for range lookups, the inherent disadvantage is that elements are ordered. Binary search tree is a basic realization of half-fold searching.

Login MySQL Database error message error 1045 (28000) is as follows:[[email protected] ~]# mysql-uroot-p fanshineenter password:error 1045 (28000): Access denied for user ' root ' @ ' Localhos T ' (using Password:yes)Analysis: The existence of a

Starting with MySQL version 5.5 InnoDB is already the default table storage engineInnoDB1: Full acid support2: Row-level lock support3: Support MVCC4: Support for foreign keysMySQL Version 5.1Prior to MySQL version 5.1, InnoDB was included in the

My project is using hibernate to perform database operations.The MySQL connection timeout problem, estimated that many people have encountered: the general situation is the case, the development of the test program is normal, one to the next day out

Let's start by understanding the concept of MySQL indexing:An index is a special file that contains reference pointers to all the records in the data table. More generally, the database index is like a directory in front of a book, can speed up the

What is a MySQL databaseTypically, a database is a collection of data, and a database can be a collection of files on a memory or a collection of some memory data.What we usually call MySQL database, SQL Server database and so on is actually a

If the table defines a varchar field and the number is passed in, an implicit conversion occurs.1. Table DDL2, the SQL to pass int3. String-Passed SQLTake a closer look at the table structure, the field type of RID:　　When the user comes in int,

First, test the version of Mysql 5.6.And then look at the trigger syntax.CREATE user | Current_User} trigger_name ] trigger_time for each trigger_event ROW tbl_name trigger_body : trigger_time {before | After} trigger_event :

The source installation of MySQL has gone through the creation of libraries, the selection of libraries, the creation of tables, the insertion of data after the backup occurred-bash:mysqldump Command not foundError, which is an issue with the

In a transaction, each correct atomic operation is executed sequentially until an incorrect atomic operation is encountered, at which point the transaction rolls back the previous operation. Rollback means that if a previous insert operation is

A transaction is the execution unit of a DBMS. It is made up of a limited number of database operation sequences. But not any database operation sequence can be a transaction. In general, transactions are required to meet 4 conditions

Original address: http://www.2cto.com/database/201108/100546.htmlThe MYSQLD server maintains two variables. Global variables affect the global operation of the server. Session variables affect specific client connection-related operations.When the

Mysql> DESC MYSQL. USER \g***************************1. Row ***************************Field:hostType:Char( -)Null:noKey:priDefault:Extra:***************************2. Row ***************************Field:userType:Char( -)Null:noKey:priDefault:Extra:

MySQL has a fool-style installation and a green installation of two versions: Fool styleFool-type installation just need to set up the path of installation, server type, account and password, types of access and other basic operations, its

The MySQL server works in different SQL modes and can be applied in different ways for different clients. In this way, the application can tailor the server operation to suit its needs. Such patterns define the SQL syntax that MySQL should support,

(i) about the storage engineCreating an appropriate index is one of the most important techniques in SQL performance tuning. Before learning to create an index, learn about MySQL's architectural details, including how it is organized on the hard

Full-text indexing has been supported since MySQL 4.0, but the default minimum index length for MySQL is 4. If the English default value is reasonable, but the majority of Chinese words are 2 characters, which results in less than 4 words can not be