One of the database review

About Database programming

1. Simple Introduction to MySQL Database

2.JDBC (Java code to manipulate database)

3.JDBC ( transactional database connection pool)

1. Common Database

1.Oracle database (Large)--oracle

2.db2

3.SQLserver (Medium)

4.MySQL (small)--oracle

Mysql6 before is free, open source.

2. What is a database?

Persistent Devices:

1.IO

2. Database

is a file system that operates data in a file system through a standard SQL language--data that is used to store software systems.

3. What kind of data is stored in the database?

Relational data (somewhat similar to a book)

4. Description:

For example: Mall system

Goods, orders, users

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For example, the above three can be said to be entities, represented by a rectangle

The corresponding attribute is represented by an ellipse.

And the relationship between entities is represented by a diamond.

Installation and uninstallation of 5.mysql

1. Uninstall

1. If the data file is separated from the installation file, you should find its location

2. Delete the database normally and delete it in Control Panel

3. Delete data files

4. Delete the remaining data files from MySQL

2. Installation

Attention:

The default port for MySQL is 3306

Character Set selection Utf-8

Service Name:mysql

3. Testing

Open Terminal input: Mysql-u root-p

Enter the password you have set: * * *

If there is a mysql>, it means success.

4. Password reset

1.win environment, enter SERVICE.MSC in "Run" to open all services, locate the corresponding service (find the path) and stop it

2. Enter MySQL under Terminal--skip-grant-tables start service cursor does not move (do not close the window).

3. New open terminal input mysql-u root-p no password required

Use MySQL

Update user set Passwd=password (ABC) Where

User=root

4. Close two terminals, end the MySQL process in Task Manager, and output exit.

5. Restart the MySQL service on the Service Management page

Password modification Complete

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MySQL data server and database and table relationships (including relationships), and finally the client to access

MYSQL-H host name-P Port-U user Name---Enter password

If you have a MySQL server installed on your computer (referring to the software)

The terminal input Mysql-u root-p

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Storage of tables

column field (property), behavior record

The fields in the table correspond to the properties in the class

Table records correspond to specific objects in the class

Class user{

int id;

String name;

int age;

}

User U=new user ();

U.id=1;u.name= "Zhangsan"; u.age=20;

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SQL Introduction

SQL Structured Query Language

SQL is a non-procedural language (no correlation between statements, relatively independent)

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SQL classification

The DDL data definition language is used to define databases, tables, etc.

DML Database Manipulation language used to delete and change the search

DCL Data Control Language user Rights control

DQL Data Query Statement (*) Select

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Basic Database Operations

1. Create/Use/delete database

Create database name;

Use database name

drop database name;

2. Create a database can specify a set of encoding and validation rules

Character Set: Specifies the encoding set used by the database

COLLATE: Specifying how database character sets are compared

Create database data name character set encoding set

Collate check;//with a check rule

Create database name character set= "Utf-general-ci";//Search Manual

Create database name character set= "UTF8";

show databases;

To display a database that already exists

View the definition information for the MYDB2 database that you created earlier

Show CREATE Database mydb2;

Modify the database and change the character encoding (learn)

ALTER DATABASE data name character set= "encoding set" collate= "checksum";

Create database name character set= "GBK";

Show create database name;

ALTER DATABASE data name character set= "encoding set" collate= "checksum";

Switch database

Use db_name;

View the database currently in use

Select Database ();

......

(Add and revise, function, trigger, view, etc. see what you've done in the past.)

One of the database review