Database connection for Java basic Learning

Database operation mysql

Add, delete, check and correct

Mysql > show databases

Database display mysql > use java12

Use the database mysql > drop table person

Delete form

Query OK, 0 rows affected (0.01 sec)

Mysql > create table person (age int (4), name varchar (20), telNum varchar (14))

Query OK, 0 rows affected (0.01 sec)

Create a table named personmysql > insert into person (age,name,telNum) values (20, "AA", "13603711234")

Query OK, 1 row affected (0.02 sec)

Insert data mysql > update person set telNum = "13838260132" where name = "CC"

Query OK, 1 row affected (0.00 sec)

Update data mysql > delete from person where age = 20

Query OK, 1 row affected (0.00 sec)

Delete of table data / / update data table Chinese error because no character encoding was specified when the database was created

Mysql > update person set name = "Zhang San" where telNum = "18603710987"

ERROR 1366 (HY000): Incorrect string value:'\ xD5\ xC5\ xC8\ xFD' for column 'name'

At row 1

Create a database that can store Chinese characters / / insert multiple records to report an error

Mysql > insert into person (age,name,telNum) values (22, "DD", "110") (23," EE "," 120")

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that

Corresponds to your MySQL server version for the right syntax to use near'(23, "

EE "," 120s ")'at line 1

Connection between Java and database

First, set up the driver:

DriverManager.registerDriver (new Driver ())

-then establish a connection

Connection conn=DriverManager.getConnection ("jdbc:mysql://localhost:3306/computer", "root", "root")

Establish a SQL statement

Statement statement= (Statement) conn.createStatement ()

ResultSet resultSet=statement.executeQuery ("select * from user"); data processing

Traverse the data and receive it

While (resultSet.next ()) {

String name=resultSet.getString ("name")

Double heigh=resultSet.getDouble ("heigh")

String sex=resultSet.getString ("sex")

Int weight=resultSet.getInt ("weight")

System.out.println ("name" + name+ "height" + heigh+ "gender" + sex)

}

Create four accepted objects to accept the data.