Java JDBC:更改表 [英] Java JDBC: Altering table

问题描述

我希望对该表进行以下更改:

I wish to make the following alterations to this table:

添加:状态列(varchar(20))日期(时间戳)列

Add: Column for state (varchar(20)) column for date (timestamp)

我不确定该怎么做

String createTable = "Create table aircraft ("
                        +"aircraftNumber int,"
                        +"airLineCompany varchar(20),"
                        +"departureAirport varchar (20),"
                        +"fuelPercentage int,"
                        +"passengerCount int);";

推荐答案

要在数据库表中添加列，请使用

To add columns in a database table, you use the ALTER TABLE statement:

ALTER TABLE aircraft
    ADD COLUMN state VARCHAR(20), 
    ADD COLUMN dateCreated DATETIME

_{请注意，由于两个原因，我不使用 date 作为字段的名称:1)在大多数数据库引擎中，它是保留关键字； 2)表字段名必须为易于理解的是，名为 date 的字段对当前模型完全没有任何价值，该日期是:创建日期，最后更新日期，飞机到达日期，飞机事故发生日期?}

_{Note that I don't use date as name for your field for two reasons: 1) It is a reserved keyword in most database engines, 2) A table field name must be easy to understand for readers, A field named date adds no value at all to the current model, which date: date of creation, date of last update, date of aircraft arrival, date of aircraft accident?.}

然后，在Java中，使用 Statement#execute 以在JDBC中执行任何DDL语句.

Then, in Java, use Statement#execute to perform any DDL statement in JDBC.

总结一下:

String sql = "ALTER TABLE aircraft "
    + "ADD COLUMN state VARCHAR(20), "
    + "ADD COLUMN dateCreated DATETIME";
Connection con = ...
Statement stmt = con.createStatement(sql);
stmt.execute();

这篇关于Java JDBC:更改表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！