Java Mysql 简明教程

Java & MySQL - Drop Database Example

本章提供了一个使用 JDBC 应用程序删除现有数据库的示例。在执行以下示例之前，请确保您具备以下条件 -

This chapter provides an example on how to drop an existing Database using JDBC application. Before executing the following example, make sure you have the following in place −

To execute the following example you need to replace the username and password with your actual user name and password.
Your MySQL is up and running.

NOTE - 这是一个严肃的操作，在着手上删除数据库之前，您必须做出一个坚定的决定，因为您数据库中的所有内容都将丢失。

NOTE − This is a serious operation and you have to make a firm decision before proceeding to delete a database because everything you have in your database would be lost.

Required Steps

创建新的数据库使用 JDBC 应用程序需要执行以下步骤：

The following steps are required to create a new Database using JDBC application −

Import the packages − Requires that you include the packages containing the JDBC classes needed for database programming. Most often, using import java.sql.* will suffice.
Open a connection − Requires using the DriverManager.getConnection() method to create a Connection object, which represents a physical connection with a database server.
Deleting a database does not require database name to be in your database URL. Following example would delete STUDENTS database.
Execute a query − Requires using an object of type Statement for building and submitting an SQL statement to delete the database.
Clean up the environment − try with resources automatically closes the resources.

Sample Code

将以下示例复制并粘贴到 TestApplication.java 中，如下进行编译和运行：

Copy and paste the following example in TestApplication.java, compile and run as follows −

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class TestApplication {
   static final String DB_URL = "jdbc:mysql://localhost/";
   static final String USER = "guest";
   static final String PASS = "guest123";

   public static void main(String[] args) {
      // Open a connection
      try(Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
         Statement stmt = conn.createStatement();
      ) {
         String sql = "DROP DATABASE STUDENTS";
         stmt.executeUpdate(sql);
         System.out.println("Database dropped successfully...");
      } catch (SQLException e) {
         e.printStackTrace();
      }
   }
}

现在让我们如下编译上述示例：

Now let us compile the above example as follows −

C:\>javac TestApplication.java
C:\>

运行 TestApplication 时，它会生成以下结果：

When you run TestApplication, it produces the following result −

C:\>java TestApplication
Database dropped successfully...
C:\>