java修改mysql表

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

public class ModifyTableExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String user = "username";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, user, password);
             Statement stmt = conn.createStatement()) {

            // 添加新列
            String addColumnSQL = "ALTER TABLE mytable ADD COLUMN new_column VARCHAR(255)";
            stmt.executeUpdate(addColumnSQL);

            // 修改列的数据类型
            String modifyColumnSQL = "ALTER TABLE mytable MODIFY COLUMN existing_column INT";
            stmt.executeUpdate(modifyColumnSQL);

            // 删除列
            String dropColumnSQL = "ALTER TABLE mytable DROP COLUMN old_column";
            stmt.executeUpdate(dropColumnSQL);

            System.out.println("Table modified successfully!");

        } catch (SQLException e) {
            System.err.println("Error modifying table: " + e.getMessage());
        }
    }
}