update primary key mysql

Reproduced: http://blog.csdn.net/sunrise918/article/details/5575054 In the past few days, I have thought about logical primary keys, business primary keys, and composite primary keys. I also searched for some discussions on the Internet. For more

Mysql auto-incrementing column leads to duplicate primary key issue analysis..., mysql primary key A few days ago, the development of shoes reported a problem of using the load data infile command to import data primary key conflicts. After analysis,

Concept:A primary key (primary key) uniquely identifies a property or group of properties for a row in a table. A table can have only one primary key, but there may be multiple candidate indexes. Primary keys often form referential integrity

In some cases we need to update the status of a record in the datasheet and then take it out, but if you don't have a primary key to confirm the unique record before the update, there's no way to know which record is being updated.To illustrate the

What are the differences among KEY, primary key, unique key, and INDEX in MySQL? mysqlunique You can split the questions raised in the questions to solve them step by step. In MySQL, KEY and INDEX are synonymous. This problem can be simplified to

Background knowledge:MySQL has three levels of Lock: page level, table level, row level.The MyISAM and memory storage engines use table-level locks (table-level locking), BDB storage engines use page locks (page-level locking), but table-level locks

The recent online frequent occurrence of slave delay, after the detection of the user in the deletion of data, due to the table primary key of the missing primary key, while deleting the condition is not indexed, or delete the condition of the

Original: MySQL primary key design[TOC]In the process of the project encountered a seemingly very basic problem, but in-depth thinking has led to a lot of problems, I think it is necessary to take this learning process to record.MySQL primary key

Set MySQL data table primary key: Use the "PRIMARY key" keyword to create a primary key data column. The primary key column is set to not allow duplicate values, in many cases combined with "auto_increment" incrementing numbers. As shown in the

First, what is the primary key, foreign key:There are several attributes in a record in a relational database, which can be a primary key if one of the attribute groups (note is a group) uniquely identifies a record:Student Table (School number,