MySQL

The difference between char and varchar char (13) length fixed, such as ' www.jb51.net ' storage requires space 12 characters varchar (13) variable length as ' www.jb51.net ' requires storage space of 13 characters, From the above you can see

HTML and PHP, MySQL interaction Why should I use a database? World Wide Web (WWW) is more than just a place to provide information. If you have something, make a website, you can share it with people all over the world. But this is not a very easy

MySQL's InnoDB expansionin order to add a data file to the tablespace, first close the MySQL database, edit the my.cnf file, confirm the InnoDB ibdata file and MY.CNF configuration is consistent, there are two situations:Configuration of 1.MY.CNF

Friend Host (Windows 2003 + IIS + PHP + MySQL) recently the MYSQL service process (Mysqld-nt.exe) CPU occupancy rate of total 100% high. This host has 10 or so database, respectively, to 10 web site calls. According to a friend test, resulting in

1. Database download MySQL official website: http://www.mysql.com/, database download address: http://www.mysql.com/downloads/. From the official website can find two kinds of packages, one is EXE installer, the other is a zip compression package.

After MySQL exports one sql: DELIMITER $$ DROP TRIGGER IF EXISTS ' Updateegopriceondelete ' $$ CREATE TRIGGER ' Updateegopriceondelete ' after the DELETE on ' CustomerInfo ' For each ROW BEGIN DELETE from Egoprice WHERE

This article for everyone to share the PHP operating environment to build installation graphics and text tutorials for your reference, the specific contents are as follows Install Apache: 1, do not install into a Chinese-language directory: 2,

Mysqlworkbench is a recently released Visual Database design tool for MySQL AB. This tool is a dedicated tool for designing MySQL databases. Download Address: http://www.jb51.net/database/29494.html Mysqlworkbench has many functions and features;

MySQL usually completes the distinct operation using groupby (essentially a sort action), and if the distinct operation is combined with the by-order operation, a temporary table is usually used. This can affect performance. In some cases, MySQL can

In computer science, a lock is a synchronization mechanism used to forcibly restrict access to resources in the execution of multiple threads, which is used to guarantee the satisfaction of mutex requirements in concurrency control. In the DBMS,

One of the most powerful features of MySQL Proxy is the end of "Read and write parting (Read/write splitting)". It works by having the primary database process a transactional query and processing a select query from a database. Database replication

Open a common query logthe general log will not open for performance reasons. Slow log can locate some performance-related SQL, and general log logs all of the SQL. mysql5.0 version, if you want to open slow log, general log, need to restart,

I. Environmental description1, Server role 2. System environmentCentOS 6.2 x86_64 3. Environmental requirements(1), MySQL 5.0 and above (used to store the data collected by the monitoring system)(2), Apache 2.2 and above (WEB server running

Stored procedures and functions define a collection of SQL statements in a database, and then call those stored procedures and functions directly to execute a defined SQL statement. Stored procedures and functions can prevent developers from writing

Suppose we have two tables, a table that holds product information for the product table, which contains price list prices; Another table is the Productprice table, and we want to update the Price field in the Productprice table to 80% of the price

Introduction to the Database engine The MySQL database engine depends on how MySQL was compiled at the time of installation. To add a new engine, you must recompile MySQL. By default, MySQL supports three engines: ISAM, MyISAM, and heap. The other

Today continue to see the teacher to recommend the simple and simple MySQL database development This book, see INNODB Database Foreign Key Association problem, encountered a problem, the book is written on the parent table can be modified to sync to

MySQL "on DUPLICATE KEY UPDATE" syntaxIf on DUPLICATE KEY UPDATE is specified at the end of the INSERT statement, and the insert row causes duplicate values to occur in a unique index or primary key, UPDATE is performed on the row where the

I test myself, many characters become '? '。 The database connection is already using the UTF8 character set: Copy Code code as follows: Define ("Mysql_encode", "UTF8"); mysql_query (' SET NAMES '. Mysql_encode, $conn) or Die (

PHP low-level programming Brothers to look at this problem, I make the following statement, I hope to be able to objectively understand the advantages and disadvantages of this enum field: Fat brother Point of view:An enum has advantages. But