MySQL

Differences between char and varcharChar (13) is fixed in length. For example, the storage space of 'www .jb51.net' must be 12 characters long.Varchar (13) Variable Length: for example, 'www .jb51.net' requires a bucket of 13 characters,From the

At the same time, the online access volume continues to increase. For servers with 1 GB of memory, the server even crashes every day or gets stuck from time to time. This problem has plagued me for using MySQL for more than half a month. scalable

Two MySql service applications1. How to install two MySql services on the same system.Install Version 5.0, and then Install Version 5.1. I am using mysql-5.0.45-win32.zip and mysql-5.1.28-rc-win32. Note that the Configuration Port Number installed

G, the solution is as follows:In the/var/lib/mysql directory, delete ibdata1, ib_logfile1, and ib_logfile0, and restart MySql to recreate the above files:Mysqladmin-uroot-p shutdownSudo mysqld_safe &Done!The following are other articles on the

You only need to follow the three steps below, and everything is under your control:Step 1: configure the Backup Directory code on the server:--------------------------------------------------------------------------------Mkdir/var/lib/mysqlbackupCd/

1. If the connection between the client and the server needs to span and pass through an untrusted network, you need to use an SSH tunnel to encrypt the communication between the client and the server.2. Use the set password statement to modify the

Up to 16 columns.Create table test (F1 int,F2 int,F3 int,F4 int,F5 int,F6 int,F7 int,F8 int,F9 int,F10 int,F11 int,F12 int,F13 int,F14 int,F15 int,F16 int,F17 int);Create index idx_test_16 on test (f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12,

The database file is large, about 70 GB,For normal migration, You need to export data in the original database and then import data in the new database.After careful consideration, is the format of MySQL database file storage identical in different

I. INSERT and REPLACEBoth INSERT and REPLACE statements INSERT new data into the table. The syntax of these two statements is similar. The main difference between them is how to process repeated data.1. General INSERT usage The INSERT statement in

The basic principle is to allow the primary database to process transactional queries, but to process SELECT queries from the database. Database Replication is used to synchronize changes caused by transactional queries to the slave database in the

I believe that many webmasters or independent Blog bloggers have the need to back up databases. Of course, there are many plug-ins that can help you complete this task in a rich Blog system such as WordPress. If you need to back up the database by

I hope this book will be able to talk to you like an expert, so that you can learn the required knowledge with simple questions and examples. In order to achieve this purpose, I will gradually establish concepts for everyone from every detail, and

Back up old dataStop old ServerDelete the mysql service from the windows System Service and run the following command:C: \> C: \ mysql \ bin \ mysqld -- remove install mysql using an executable installation file, or decompress a binary compressed

I. data definition language)A document language is a language defined for the format and form of a document. It is the first thing that every database needs to create, the table relationships, column primary keys in the table, and the reference

1. Stop mysql services first.2. Change the master path of database storage in MySQL configuration file My. iniOpen the default MySQL installation folder C: \ Program Files \ MySQL Server 5.1 In my. INI file, click "edit" and "Search" at the top of

The scenario is as follows: I have a KV table. The table creation statement is as follows: Copy codeThe Code is as follows:Create table 'dkv '('K1 'int (11) not null default '0 ','K2' int (11) not null default '0 ','Val 'varchar (30) default

I. Data Control Statement (DML) 1. INSERT (INSERT the record statement into the data table)Insert into Table Name (field name 1, field name 2 ,......) VALUES (value 1, value 2 ,......);Insert into Table Name (field name 1, field name 2 ,......)

SQL statement used to query the disk space of all databases: Copy codeThe Code is as follows:Select TABLE_SCHEMA, concat (truncate (sum (data_length)/1024/1024, 2), 'mb') as data_size,Concat (truncate (sum (index_length)/1024/1024, 2), 'mb') as

The following prompt appears in the PHP 4.4.1 + MySQL 5.1 environment: Copy codeThe Code is as follows:File 'C: \ mysql \ share \ charsets \?. Conf 'not found (Errcode: 22) Character set' # 33' is not a compiled character set and is not specified in

Copy codeThe Code is as follows:Mysql> select binary 'abc' = 'abc' COM1, 'abc' = 'abc' COM2;+ -------- + ----------- +| COM1 | COM2 |+ -------- + ----------- +| 0 | 1 |+ --------- + ----------- +1 row in set (0.00 sec) (Just a few! 4. *