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JDBC quick start

2022-07-25 08:53:00 【Hua Weiyun】

Catalog

JDBC brief introduction

JDBC Concept

JDBC The essence

JDBC benefits

Relationship diagram ：

MySQLjar Package download address

JDBC brief introduction

JDBC Concept

①JDBC Is the use of Java A set of language operation relational data records API
② The full name is (Java DataBase Connectivity), It's called Java Database connection .

JDBC The essence

① official （sun company ） A set of rules defined to operate all relational databases , That is to say Interface .
② Each database manufacturer to implement this set of interface , Provide database driver jar package .
③ We can use this interface （JDBC） Programming , The code that actually executes is the driver jar The implementation class in the package

JDBC benefits

① Each database manufacturer uses the same interface ,Java The code does not need to develop different codes for different databases
② The underlying database can be replaced at any time , Access database Java The code is basically unchanged

Relationship diagram ：

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MySQLjar Package download address

MySQL :: MySQL Community Downloadshttps://dev.mysql.com/downloads/ Generally choose this option independent of the platform

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① Create a new project

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② Then build a module

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③ In the new jdbc-demo Create a... In the module lib Catalog , take mysql Of jar Copy and paste the package here

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④ Import the jar Package setting scope ( Right click jar package )

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⑤ stay src Next, create a class

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⑥ Class ：

package com.jdbc;import com.mysql.jdbc.Connection;import java.sql.DriverManager;import java.sql.Statement;public class JDBCDemo {    public static void main(String[] args) throws Exception {        //1、 Registration drive         Class.forName("com.mysql.jdbc.Driver");       //2、 Get the connection          //url The format is ："jdbc:mysql://mysql Of ip: Port number / Operational database "        String url="jdbc:mysql://127.0.0.1:3306/kc_db01";        //username Is your mysql user name         String username="root";        //password Is your mysql password         String password="123456";        Connection conn= (Connection) DriverManager.getConnection(url, username, password);        //3、 Definition sql        String sql="update emp set salary=666 where ename='zhangsan'";        //4、 Access to perform sql Of Statement object         Statement stat=conn.createStatement();        //5、 perform sql sentence ,count Is the number of lines affected         int count=stat.executeUpdate(sql);        //6 Processing results         System.out.println(" Number of rows affected :"+count);        //7、 Release resources ( Open first and then release )        stat.close();        conn.close();    }}

Before the database ：

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