创建表DDL 、增删改DML、DQL查询操作

1.创建一张Student表，创建表DDL

 1 import static org.junit.Assert.*;
 2
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.Statement;
 6
 7 import org.junit.Test;
 8
 9 /**
10  * 创建一个学生表，
11  * SQL语句：create table t_student(id int prinmary key auto_increment,name varchar(20),age int)
12  *
13 */
14
15 public class DDLTest {
16     private static final String str = null;
17
18     @Test
19     public void testCreateTable() throws Exception {
20         //贾琏欲执事，贾--加(贾)载注册驱动，琏--获取数据库连(琏)接对象 ，创建语(欲)句，执(执)行SQL语句，释(事)放资源(先开后关)
21         String sql = "create table t_student (id int primary key auto_increment,name varchar(50),age int)";
22
23         //1.加载注册驱动
24         Class.forName("com.mysql.jdbc.Driver");
25
26         //2.获取数据库连接对象
27         Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbcdemo", "root", "root");
28
29         //3.创建语句
30         Statement st = conn.createStatement();
31
32         //4.执行SQL语句
33         st.executeUpdate(sql);
34
35
36         //5.释放资源(先开后关)
37         st.close();
38         conn.close();
39     }
40
41
42 }

增删改DML：

 1 import static org.junit.Assert.*;
 2
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.Statement;
 6
 7 import org.junit.Test;
 8 //插入数据 SQL:insert into t_student (name,age) values(‘小乔‘,30)
 9 public class DMLTest {
10
11
12     @Test
13     public void testInsert() throws Exception {
14         String sql = "insert into t_student (name, age) values(‘大桥‘,30)";
15         //贾琏欲执事
16         //1.加载注册驱动
17         Class.forName("com.mysql.jdbc.Driver");
18
19         //2.获取数据库连接对象
20         Connection conne = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbcdemo", "root", "root");
21
22         //3.创建语句
23         Statement St = conne.createStatement();
24
25         //4.执行SQL语句
26         St.executeUpdate(sql);
27
28         //5.释放空间(先开后关)
29         St.close();
30         conne.close();
31     }
32         /*
33          *
34          * 修改操作：update t_student set name = ‘貂蝉‘,age = 35 where id = 3
35          *
36          *
37          */
38         @Test
39         public void testUpdate() throws Exception {
40             String sql = "update t_student set name = ‘貂蝉‘,age = 35 where id =3";
41             //贾琏欲执事
42             //1.加载注册驱动
43             Class.forName("com.mysql.jdbc.Driver");
44
45             //2.获取数据库连接对象
46             Connection conne = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbcdemo", "root", "root");
47
48             //3.创建语句
49             Statement St = conne.createStatement();
50
51             //4.执行SQL语句
52             St.executeUpdate(sql);
53
54             //5.释放空间(先开后关)
55             St.close();
56             conne.close();
57
58
59     }
60         /*
61          * 删除数据SQL：delete from t_student where id = 4
62          *
63          */
64
65         @Test
66         public void testDelete() throws Exception {
67             String sql = "delete from t_student where id = 4";
68             //贾琏欲执事
69             //1.加载注册驱动
70             Class.forName("com.mysql.jdbc.Driver");
71
72             //2.获取数据库连接对象
73             Connection conne = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbcdemo", "root", "root");
74
75             //3.创建语句
76             Statement St = conne.createStatement();
77
78             //4.执行SQL语句
79             St.executeUpdate(sql);
80
81             //5.释放空间(先开后关)
82             St.close();
83             conne.close();
84
85
86     }
87
88 }

DQL查询操作

原文地址：https://www.cnblogs.com/abcdjava/p/10886933.html