达梦图数据库使用手册

《达梦图数据库使用手册》是一份详细介绍如何使用达梦图数据库的技术文档。本手册旨在帮助开发人员快速上手并掌握达梦图数据库的使用。

一、数据库连接

1. 首先，需要下载并安装达梦图数据库。

2. 在代码中创建数据库连接对象：

import java.sql.*;

public class DBUtil {
   private static final String driverClassName = "dm.jdbc.driver.DmDriver";
   private static final String url = "jdbc:dm://localhost:5236/xxx";
   private static final String username = "username";
   private static final String password = "password";
   private static Connection conn;

   public static Connection getConnection() throws SQLException, ClassNotFoundException {
      if (conn == null || conn.isClosed()) {
         Class.forName(driverClassName);
         conn = DriverManager.getConnection(url, username, password);
      }
      return conn;
   }
}

二、数据操作

1. 增加数据

import java.sql.*;

public class Insert {
   public static void main(String[] args) throws SQLException, ClassNotFoundException {
      Connection conn = DBUtil.getConnection();
      String sql = "insert into student (name, age) values (?, ?)";
      PreparedStatement pstmt = conn.prepareStatement(sql);
      pstmt.setString(1, "张三");
      pstmt.setInt(2, 18);
      pstmt.executeUpdate();
      pstmt.close();
      conn.close();
   }
}

2. 删除数据

import java.sql.*;

public class Delete {
   public static void main(String[] args) throws SQLException, ClassNotFoundException {
      Connection conn = DBUtil.getConnection();
      String sql = "delete from student where name = ?";
      PreparedStatement pstmt = conn.prepareStatement(sql);
      pstmt.setString(1, "张三");
      pstmt.executeUpdate();
      pstmt.close();
      conn.close();
   }
}

3. 修改数据

import java.sql.*;

public class Update {
   public static void main(String[] args) throws SQLException, ClassNotFoundException {
      Connection conn = DBUtil.getConnection();
      String sql = "update student set age = ? where name = ?";
      PreparedStatement pstmt = conn.prepareStatement(sql);
      pstmt.setInt(1, 19);
      pstmt.setString(2, "张三");
      pstmt.executeUpdate();
      pstmt.close();
      conn.close();
   }
}

4. 查询数据

import java.sql.*;

public class Select {
   public static void main(String[] args) throws SQLException, ClassNotFoundException {
      Connection conn = DBUtil.getConnection();
      String sql = "select * from student";
      PreparedStatement pstmt = conn.prepareStatement(sql);
      ResultSet rs = pstmt.executeQuery();
      while (rs.next()) {
         System.out.println("id:" + rs.getInt("id") + " name:" +