一、数据更新语句的命令格式如下:
UPDATE <table_name> SET column_name = 'xxx' WHERE <条件表达式>
- 在更新数据的时候既可以使用Statement实例通过UPDATE语句完成,也可以利用PreparedStatement实例通过执行UPDATE语句来完成,还可以利用CallableStatement实例通过执行存储过程完成。
- (1)利用Statement实例通过执行静态UPDATE语句举例
String sql = "update tb_record set salary=3000 where duty='部门经理'";
statement.executeUpadate(sql);
- (2)利用PreparedStatement实例通过执行动态UPDATE语句
String sql = "update tb_record set salary=? where duty = ?";
PreparedStatement prpdStmt = connection.prepareStatement(sql);
prpdStmt.setInt(1,3000);
prpdStmt.setString(2,"部门经理");
prpdStmt.executeUpdate();
- (3)利用CallableStatement实例执行存储过成修改数据的实例
String call = "{call pro_record_update_salary_by_duty(?,?);
CallaleStatement cablStmt = connection.prepareCall(call);
cablStmt.setInt(1,3000);
cablStmt.setString(2,"部门经理");
cablStmt.executeUpdate();
- 无论使用哪种实例修改数据,都需要执行executeUpdate()方法,该方法将会返回一个int型值,用于记录被修改的条数
package com.bjpowernode.java_learning;
import java.sql.Statement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class D137_1_UpdateInformation {
private static final String URL = "jbdc:Access:///e:xsgl.mdb";
static {
try {
Class.forName("com.hxtt.sql.access.AccessDriver");
}catch(ClassNotFoundException e) {
e.printStackTrace();//输出捕捉到的异常信息
}
}
public static void main(String[] args) {
try {
Connection conn = DriverManager.getConnection(URL);
Statement statement = conn.createStatement();
String sql = "update tb_record set Salary=Salary + 10 where Duty='部门经理' ";
statement.executeUpdate(sql);
statement.close();
conn.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
}
- 执行该语句之后部门里面所有的部门经理薪水都会涨100
- 接下来使用PreparedStatement来操作一遍
package com.bjpowernode.java_learning;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
public class D137_2_PreparedStatementUpdate {
private static final String URL = "jbdc:Access:///e:xsgl.mdb";
static {
try {
Class.forName("com.hxtt.sql.access.AccessDriver");
}catch(ClassNotFoundException e) {
e.printStackTrace();//输出捕捉到的异常信息
}
}
public static void main(String[] args) {
try {
Connection conn = DriverManager.getConnection(URL);
String[][] infos = {{"A","200"},{"B","100"}};
String sql = "update tb_record set salary=salary+? where cname=?";
PreparedStatement prpdStmt = conn.preparedStatement(sql);
prpdStmt.clearBatch();
for(int i=0;i<infos.length;i++) {
prpdStmt.setInt(1, Integer.valueOf(infos[i][1]).intValue());
prpdStmt.setString(2, infos[i][0]);
prpdStmt.addBatch();
}
prpdStmt.executeBatch();
prpdStmt.close();
conn.close();
}catch(SQLException e) {
e.printStackTrace();
}
}
}
二、源码: