如何编辑表中（添加或更新）列，以及如何删除一个表？

解决方法

下面的示例使用 create, alter & drop的SQL命令来创建，编辑或删除表

import java.sql.*;

public class jdbcConn {
   public static void main(String[] args) throws Exception{
      Class.forName("org.apache.derby.jdbc.ClientDriver");
      Connection con = DriverManager.getConnection
      ("jdbc:derby://localhost:1527/testDb","username",
      "password");
      Statement stmt = con.createStatement();
      String query ="CREATE TABLE employees 
      (id INTEGER PRIMARY KEY,
      first_name CHAR(50),last_name CHAR(75))";
      stmt.execute(query);
      System.out.println("Employee table created");
      String query1 = "aLTER TABLE employees ADD 
      address CHAR(100) ";
      String query2 = "ALTER TABLE employees DROP 
      COLUMN last_name";
      stmt.execute(query1);
      stmt.execute(query2);
      System.out.println("Address column added to the table 
      & last_name column removed from the table");
      String query3 = "drop table employees";
      stmt.execute(query3);
      System.out.println("Employees table removed");
   }	
}

结果

上面的代码示例将产生以下结果。该结果可能会不同。

Employee table created
Address column added to the table & last_name 
column removed from the table
Employees table removed from the database