about mysql

There is index (A,B,C)-the combined Index multi-field is ordered and is a complete btree index. The following criteria can be used on the combined index query: A>5 A=5 and B>6 A=5 and B=6 and c=7 A=5 and

Recently encountered the MySQL field of the self-enhancement problem, need to temporarily deal with, and then by the way to make up for the missed lesson, so that there is an article.1. What is self-increment?He is a field property that is used to

1. Online DDLIn MySQL 5.1 (with InnoDB Plugin) and 5.5, a new feature called Fast Index Creation (FIC), is to add or remove the two-level index , you can not copy the original table. For the previous version of the addition of the index to remove

MySQL database installation defaults to local access only, if you need remote connection to do something according to different operating systemWindows:The newly installed MySQL cannot log on locally and is displayed as a 1045 errormysql#1045

Open cmd terminal, start MySQL, execute command net start MySQL;Log in as root userMysql-u-root-p;If an error is1045 (28000foruser'root'@'localhost ' (using Password:yes)It is expected that after the mysql5.6 version, you need to enter a

about MySQL database optimizationIn my humble opinion, the database is optimized to optimize storage and query speedAt present the main optimization I think is to optimize the query speed, query speed, improve the user's experienceI think that the

First, background:The "Go to IoE" is the essence of "distributed + Open source" architecture instead of "centralized + closed" architecture, into a thorough cloud computing service model. To "IE" easy, and should go, the key really can save money,

To create the user's syntax: Create user ' username ' @host [identified by [password] ' password ']; Username: User Name Host: hostname, local host can use localhost or IP address, but other computers must use IP address to log on

Introduction to Stored Procedures Stored Procedures (Stored Procedure) are in a large database system, a set of SQL statements to complete a specific function, stored in the database, after the first compilation after the call does not need to

Because the MySQL database directly corresponds to the data directory, and the table, the trigger corresponds to the files in the directory, so that the MySQL identifier is case sensitive not only related to the operating system, but also with what

I. Knowledge of the database1. The origin of the databasePreviously known data is stored in a file, but a file can only exist on one machine, but in reality, all the data is not stored on a machine.(1) In reality it is impossible to put all the

 Reprint Please indicate the source: The Curtain Roll westerly column (Http://blog.csdn.net/ljxfblog)The game starts the second time and starts processing the operation log. Start by putting the logs in the same table and discovering the time of day,

A while ago, due to write a program to use the database, it was downloaded in the book, but there are a lot of small problems (their desktop is not the problem, it may be my book too slag it), tangled up a good burst, think back, find problems,

MySQL has two kinds of storage engines: InnoDB and MyISAMThere are six major differences between the two: MyISAM InnoDB The difference in composition: Each myisam is stored as three files on disk. The

These two days have a very strong feeling is oneself in some special situation or hold, the brain is easy to empty or say suddenly do not know how to analyze the problem, for example, ask "hash and btree Index difference", this is difficult, as long

Initial: Due to the high CPU consumption of the newly installed server, the response is not timely troubleshooting, because the environment based on the most basic lamp architectureThink of turning on MYSQL slow_query_log slow query log for reasons

Data is increasingly inseparable from our lives, and data has different pain points and needs and special scenarios at all stages of the life cycle.Curd is the four basic requirements of data: Write, update, read, delete.Today, let's talk about the

Package Com.itheima.trans;import Java.sql.connection;import Java.sql.preparedstatement;import java.sql.ResultSet; Import Java.sql.sqlexception;import Com.itheima.util.dbutil;public class Transdemo {/* create MySQL database related SQL statement:

What is an index An index is a data structure, usually a b-tree, Hash, that stores the values of a particular column (one or more columns) in a table. Its purpose is to help the database to obtain data efficiently, quickly find the specified

1. Login SQLyog password is inconsistent with MySQL settings.2. Last installed MySQL did not uninstall clean, (Troubleshooting Delete: Search c disk Delete related files, search registry Delete relevant items, into the DOS interface Delete Service