mysql reference

If on DUPLICATE KEY UPDATE is specified at the end of an INSERT statement, and the insert row causes duplicate values to occur in a unique index or primary key, the old row update is executed, and the new row is inserted if the problem does not

For example, if column A is defined as unique and the value is 1, the following statement has the same effect, that is, if there is a a=1 in the record that is in and out, the C = C + 1 is directly updated without performing the operation of C = 3.

The time type of MySQL has the corresponding time type in JavaDate Java.sql.Date Datetime Java.sql.Timestamp Timestamp Java.sql.Timestamp Time Java.sql.Time Year Java.sql.Date to analyze ItRefer to MySQL reference manual Date:A date. The

The company's MySQL architecture has recently been upgraded, from the original one of the main more from the Drbd+heartbeat double master from, just have a new E-commerce site project will be online, with the Drbd+heartbeat dual-master one from,

When working on a very large table, you may occasionally need to run many queries to get a small subset of a large amount of data, instead of running the query on the entire table, instead of having MySQL find the few records needed each time, it

Mysql The intention of MySQL's original developers was to connect the tables with mSQL and their own quick low-level routines (ISAM). In any case, after some testing, the developer concludes that mSQL is not as fast and flexible as they need to be.

mysql| Backup | data | database 1 using mysqldump to back up and copy databases When you use the Mysqldumo program to generate a database backup file, the file contents contain the Create statement that creates the table being dumped and the INSERT

mysql| Data | Database summary In this chapter we will learn how to store information in a Web page and display it in a database. (2002-08-29-14:11:25) -------------------------------------------------------------------------------- By Wing,

When working on a very large table, you may occasionally need to run many queries to get a small subset of a large amount of data, instead of running the query on the entire table, instead of having MySQL find the few records needed each time, it

Liu Tians, 2010/07/24 14:28, Linux, Comments (67), reading (40557), Via site Original Big | In | A preface Why to introduce the second edition. Since the first edition is based on Logzilla3.0, the author has licensed restrictions after Logzilla3.0,

Features that 3.9 MySQL does not supportThis section describes features in other databases that are not available in MySQL. It describes what has been omitted and what to do when these features are needed. In general, MySQL ignores certain features

mysql| Stored Procedures | tutorials Author: MySQL AB; translation: Chen Bong Error Handling Exception Handling All right, now we're going to talk about exception handling. 1. Sample Problem:log of failures Problem example: Fault logging When an

MySQL Optimization Topic Development--Wang YaoyuFirst, SQL Optimized1. Analysis and positioning strategies1. Learn the frequency of SQL execution through show status2, location execution inefficient SQL statement: ① through slow log positioning; ②

1. Uninstall the old version of MySQLGo to the Mac terminal, enter a command to uninstallCD ~/sudo RM/usr/local/MySQLsudo RM-rf/usr/local/var/MySQLsudo RM-rf/usr/local/mysql*sudo RM-rf/library/startupitems/mysqlcomsudo

MySQL is a relational database management system, its small size, speed, the total cost of ownership is low, especially the open source of this feature, the general development of small and medium-sized web sites have chosen MySQL as the site

CSDN Blog Relocation 1. Introduction In the Web application architecture, the data persistence layer (usually a relational database) is a key core part, which has a very important impact on the performance of the system. MySQL is currently the

I didn't think it would take me two or three days to configure my MacBook for the PHP environment. Seemingly online looking for a lot of tutorials, but mostly a few years ago, and recently six months ago, the most important card in the database this,

The biggest benefit of backup is that you can recover from the loss or corruption of your database tables. Even if you are not greedy, just hope to recover part of you are also very happy, right? Sometimes, it is the MySQL administrator that causes

A variety of MySQL administration Tools <>mysql provides command-line tools mysql_install_db : MySQL Build library tool, in the source installation MySQL link we used. Mysql_safe : MySQL boot tool mysqld : MySQL master process,

MySQL Optimization related summary2016-05-31 Database concentration camp Optimization Order: Select the appropriate engine and table structure and data type Build an index and optimize SQL. Increased cache, Redis, memcache.