MySQL

http://blog.csdn.net/l1028386804/article/details/48413681 Error Analysishttps://www.cnblogs.com/fyc119/p/7529902.html Master-Slave configurationTest the next master and slave separation configuration, the basic is successful, first record the

Database: A warehouse in which data is stored and managed according to data structures.MySQL is a relational database management systemAfter MySQL is installed ...MySQL Start-up1: Find MySQL Right-click on "Services" in the control Panel to start2:

Explain shows how MySQL uses indexes to process SELECT statements and join tables. Can help select better indexes and write more optimized query statements. Using the method, add explain to the SELECT statement. mysql> explain select * from

Open URL: https://dev.mysql.com/downloads/mysql/Pull to the bottom of the page, down to download this Windows (x86, 64-bit), ZIP ArchiveAfter downloading, create a folder in the D drive, MySQL, unzip to the folderCreate a Notepad, modify the name

MySQL is an open-source database management system that is usually installed as part of the popular lamp (Linux,apache,mysql,php/python/perl) stack. It uses relational databases and SQL (Structured Query Language) to manage its data.The installation

Data typeThe so-called column type, in fact refers to the data type, that is, the unified classification of data, from a system point of view is to be able to use a unified way to manage, better use of limited space.In SQL, the data types are

Index one, introduction to the indexA data structure in the database that is designed to help users quickly find data. Similar to a directory in a dictionary, when looking up a dictionary, you can find the location of the data based on the directory,

With the continuous improvement of the information level of various industries, a variety of information management systems are widely used, the data between the systems are completely independent, forming a large number of information islands. For

The MySQL query cache saves the full result returned by the query. When the query hits the cache, the results are returned immediately, skipping the parsing, optimization, and execution phases.The query cache tracks each table involved in the query,

MySQL uses 3 kinds of locking mechanismsRow-level lock, high overhead, locking slow, deadlock, lock conflict is the highest probability, concurrency is also the highestTable-level lock, low overhead, lock fast, no deadlock, lock conflict is the

The original JOIN Connection statementSELECT SUM(Video_flowers. Number) as Num,VIDEO_FLOWERS.FLOWER_ID,Flowers.title,Flowers.image from' Video_flowers ' JOIN' Flowers ' on ' Video_flowers '.' flower_id '=' Flowers '.' id ' JOIN' video_posts '

today, using springboot to connect to Linux mysql, the period has been an error, here is a simple record of the process. Tools: idea-2017,linux-7.x,mysql-5.6.40.First, let's talk about the effects of these annotations:(1)Spring Boot

First, install Pycharm and Django not detailed said, self-BaiduSecond, the new Django project also did not sayThird, configure Django to connect to MySQL1.models.py write a class that inherits Models.modelclass Book (models. Model): name=models.

Show DATABASES can display all the databases,Show TABLES will display all the data sheets,Show all users in MySQL1. Log in to the databaseFirst of all, you need to log in to the database using the following command, note that must be root user Oh ~#

1. If multiple columns are indexed, follow the leftmost prefix rule, which refers to the query starting at the leftmost top of the index and not skipping the columns in the index.2. Do not do any operations on the index (compute, function,

Knowledge points: MySQL indexing principle complete manual (1) Knowledge points: MySQL indexing principle complete manual (2) Knowledge points: MySQL index optimization combat (3) Index principle Knowledge Review index performance analysis and

INSERT intoBookcategory (category_id,category,parent_id)VALUES(1,'Computer',0);//Specify the order of insertionsINSERT intoBookcategoryVALUES(1,'Computer',0);//Follow the default insertINSERT intoBookcategory

Clustered index: Simple concept: A table based on the primary key created by a B+ tree, the index leaf node holds all the records in the table, storage records in the physical location is continuous, a leaf node holds a corresponding record (PS: is

1. Internal connection:INNER join, Crross Join,join is an equivalent connection in MySQL that produces a Cartesian product.The join operator "," (comma) is similar, but the precedence of the comma operator differs from the other connection types.

Background: Early stage of business in order to facilitate rapid iteration, many applications have a centralized architecture, with the expansion of business scale, the system becomes more and more complex, the traffic is more and more large, have