Database Concepts
# 1 casual saved to a file in the data format is vastly different # 2. Software development directory specification defines the location data stored ps: data are stored locally # 3. Save the part of the stored data to a common where all the relevant data related to the user must be the place to find public
The MySQL database
# Is essentially a web-based application to communicate # any underlying network-based communications software are socket server - based socket communication - sending and receiving messages - SQL statement (a common standard) client - based socket communication - send and receive messages - SQL statement ps: MySQL not only supports MySQL client to operate also support other programming languages directly manipulate Python the Java c ++ PHP syntax is different
DBMS: Database Management System
Relational Database
# Can have associated limitations and data between the data and the relational database usually table structure, which means you're in a relational database first step is to determine the structure of table fields have a specific type of memory with a string name save the password with the number stored with date of birth MySQL, oracle, sqlite, db2, sql server
Non-relational databases
# Usually are stored as data k, v keys redis, mongodb (document database is very close to non-relational data relational), memcache
MySQL can actually see it as a software support remote file operations
>>> library folder list >>> file records >>> data in the file line by line, called a section of the recording header is the first line of the data table field the field name + Field Type
Installing MySQL
# In the IT industry, do not easily try the latest version of the software after the download is the MySQL server and client download down decompression: Click to open directory server: mysqld client: mysql
Start mysqld
1 Switch to the bin directory of 2 execution mysqld. PS: do pre-configured MySQL when the terminal is recommended that you run as administrator Windows + r to start an ordinary user mysql when the initial landing was not directly enter a password mysql sql statement is a semicolon does not knock you completely do not enter a semicolon default client will let you continue typing
Client Log
-h 127.0.0.1 -P 3306-uroot-MySQL - the p- can be abbreviated MySQL -uroot-- the p- If you do not enter a user name and password by default is landed guest mode function can be used in very few clients logout Exit; quit;
View
# View all the database Show Databases; # view a process tasklist | findstr Name # kill process taskkill / F / PID process ID
Production environment variable
The startup files are located in the path environment variable added to the system's
Note: After configuring a while to restart the mysql server and cmd terminal
will be made into a system service mysqld
production system services your administrator cmd terminal must be a
mysqld --install
change Password
# Without a password mysqladmin -p password-uroot-123 # under have a password mysqladmin -uroot -p123 password 123456 when the command input error can be used when \ c cancel the previous command cancel
decryption
Has now launched the server stopped # 1 to skip authentication username and password function is activated server mysqld --skip-grant- the Tables start the server to skip the authorization form # 2. Modify the administrator password corresponding to the user update mysql SET password = password the .user (123) WHERE user = ' the root ' and Host = ' localhost ' ; # 3. Close the current verification server again to the way a user name and password to start # 4 in the normal way connection username and password mysql server
Profiles
\ s View mysql server simple configuration
suffix configuration files usually are ini the end of the
mysql configuration file that comes not to modify
, but you can create a configuration file my.ini
mysql server will automatically load your my start. ini configuration in the configuration file
need to first stop the server restart to take effect after you finish modifying the configuration file
to modify the configuration file must restart the server
The basic operation of the database
library similar to folders
# Increasing Create Database DB1; # investigation show databases; check all show create database db1; single check # change ALTER Database charset = DB1 ' GBK ' ; modify codes # puncturing drop database db1; deletion library
table
You need to be specified when creating a table of library specify the library: use library name to view the current, although in the library: the SELECT Database () # increasing the Create UserInfo (the above mentioned id int, name char) the Table; # check show tables; see below a library All tables Show Create table UserInfo; desc UserInfo; <==> DESCRIBE UserInfo; # change ALTER Modify table UserInfo name char (32 ); # puncturing drop table userinfo;
recording
Create a library or specify an existing library switch to this library to create the table and then the operation record Create Database DB1; Create Table UserInfo (ID int, name char ( 32 ), password int); # increasing insert into userinfo values ( . 1, ' Jason ' , 123 ); inserting a single data iNSERT INTO UserInfo values ( . 1, ' Jason ' , 123), (2, ' Egon ' , 123), (. 3, ' Tank ' , 123 ); inserting a plurality of data # check the SELECT * from UserInfo; to query all the fields of information the SELECT name from UserInfo; query information specified field the SELECT the above mentioned id, name from. 1 WHERE ID = UserInfo or name = Tank; information field with filter conditions # change Update UserInfo SET name = ' Kevin ' WHERE ID =. 1 ; a modified data field information Update UserInfo SET name = ' Jason ' , password = 666 ID. 1 = WHERE ; a plurality of modified data fields # delete delete from UserInfo ID =. 1 WHERE ; qualified data specified delete delete from UserInfo; delete all the data in the table