mysql table

I. Introduction of the TableTable is equivalent to a file, a record in the table is equivalent to a row of the file, but a record in the table has a corresponding title, called the table field Id Name Age Sex

One, the upper limit of the number of rows1. Official documentsThere is a limit of (2^32) ^2 (1.844E+19) rows in a MyISAM table.This is the theoretical upper limit of the number of lines in MySQL, but is actually not up to2. myisam_data_pointer_size 

Recently, the new MySQL instance imported SQL data, found more than the old MySQL 100+ table, the final discovery is the MySQL table name case, the simple problem is delayed for a long time, in this record, in order to prevent the same mistake again;

1. Duplicate table structure1.1 Complete table structure with information such as primary keyCREATE table New table name like book;1.2 Only table structure, no primary key and other informationCREATE table new table name select * from books;orCREATE

Background knowledge:Table partitioning is to store logically the same range of data in the same file, just like the supermarket, put the same kind of goods in the same area, the different goods in different places. The difference is in the

The model cannot be generated because the following exception exists: ' System.Data.StrongTypingException: The Value of column ' IsPrimaryKey ' in table ' Tabledetails ' is DBNull. ---> system.invalidcastexception: The specified conversion is not

1. DescriptionWhen you delete all data for a table with auto_increment columns:(1) For the MyISAM table, the delete table in all data without any risk, random toss;(2) for the InnoDB table, in the Delete table all the data, it is possible to risk,

Foreword: Recently in the internship, to do with the MySQL related development, think of a long time ago a pen test--to see the database table structure of what kinds of methods;(i) using the describe statementOrDESC table_name;The latter is the

Task:Web project is in the Linux Tomcat deployment, MySQL is also on the above, for unknown reasons database downtime, start, database table also suddenly lost, all empty!!!!!!!! MySQL installation directory Surprised to find

MySQL under Linux database name, table name, column name, alias casing rules are like this:1, database name and table name are strictly case-sensitive;2, the table alias is strictly case-sensitive;3, the column name and the alias of the column in

ALTER TABLE logtest CONVERT to CHARACTER SET UTF8 COLLATE utf8_general_ci;To modify the database character set:The code is as follows:ALTER DATABASE db_name DEFAULT CHARACTER SET character_name [COLLATE ...];Change the default character set of the

This article mainly introduces table locks and row locksI. Table lock1. View the competition of table locksShow status like ' table_locks% '650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/7D/6E/wKiom1boADLQbZ6EAAAMg2WSYyw108.png "title=" 1

The default MySQL engine type is MyISAM,mysql>showengines;The transaction isolation mechanism is: read-committed (/etc/my.cnf view)Default Build table if the engine type is not specified, it is automatically myisam. You want to change the table to

MySQL Table Sub-queryA table subquery is a table data in which the result set returned by a subquery is n rows n columns.MySQL Table Sub-query instanceHere are two original data tables for the example: Article table: Aid

database table Basic Operations After thinking, finally the name of the blog changed to the basic operation of the database table, formerly called the SQL statement Daquan, feeling with "Daquan" this noun is too big, and the

Tag: MySQL Determines whether a field existsBackground: Today, when deploying SQL code, it is not possible to discover the way in which a previously used judgment field exists, as follows:On the internet to find a long time method, liquibase too

The following error was reported in the Select for Chinese queryERROR 1267 (HY000): illegal mix of collations (latin1_swedish_ci,implicit) and (utf8_general_ci,coercible) for operation ' =Look at the encoding of the tableShow CREATE TABLE

MySQL default link number 15 port 3306 [email protected]Create Database MyBase character Set utf-8;Use MyBase;drop table students;CREATE TABLE Students (Name Char (8),Sex char (4),Age tinyint unsigned is not NULL,Tel char (+) NULL default "-")

0x001 Issue BackgroundMySQL executes the relevant MySQL command (we performed, show procedure status) When prompted Mysql.proc table crashed, cannot be repaired (marked as crashed and last (automatic?) Repair failed)Error message: MySQL table is

This article is a MySQL table and query optimization of some practical tips for a detailed analysis of the introduction of the needs of friends under the reference The MySQL table stage is a very important link, the table structure of good or bad