数据库use命令_使用USE命令切换数据库

分手后的思念是犯贱 2022-12-06 15:27 56阅读 0赞

数据库use命令

Creating a database in [MySQL][] doesn't select it for use. You have to indicate it with the USE command. The USE command is also used when you have more than one database on a MySQL server and need to switch between them.

在[MySQL][]中创建数据库不会选择使用它。 您必须使用USE命令进行指示。 当您在一个MySQL服务器上有多个数据库并且需要在它们之间进行切换时，也会使用USE命令。

You must choose the correct database each time you start a MySQL session.

每次启动MySQL会话时，都必须选择正确的数据库。

## MySQL中的USE命令 **(** The USE Command in MySQL **)** ##

The syntax for the USE command is:

USE命令的语法为：

mysql>

For example, this code switches to the database named "Dresses."

例如，此代码切换到名为“连衣裙”的数据库。

mysql>

After you select a database, it remains the default until you end the session or choose another database with the USE command.

选择数据库后，它将保留默认值，直到您结束会话或使用USE命令选择另一个数据库为止。

## 识别当前数据库 **(** Identifying the Current Database **)** ##

If you are unsure which database is currently in use, use the following code:

如果不确定当前正在使用哪个数据库，请使用以下代码：

This [code][] returns the name of the database currently in use. If no database is currently in use, it returns NULL.

此[代码][code]返回当前正在使用的数据库的名称。 如果当前未使用任何数据库，则返回NULL。

To view a list of available databases, use:

要查看可用数据库的列表，请使用：

## 关于MySQL **(** About MySQL **)** ##

MySQL is an open-source relational database management system that is most often associated with web-based applications. It is the database software of choice for many of the web's largest sites including Twitter, [Facebook][], and YouTube. It is also the most popular database management system for small and medium-sized websites. Almost every commercial web host offers MySQL services.

MySQL是一种开源关系数据库管理系统，通常与基于Web的应用程序相关联。 它是许多Web最大站点(包括Twitter， [Facebook][]和YouTube)的首选数据库软件。 它也是最受欢迎的中小型网站数据库管理系统。 几乎每个商业网络主机都提供MySQL服务。

If you are just using MySQL on a website, you won't need to be involved with the coding—the web host will handle all that—but if you are a developer new to MySQL, you'll need to learn SQL to write programs that access MySQL.

如果您只是在网站上使用MySQL，则无需参与编码-网络主机将处理所有这些工作-但是，如果您是MySQL的新开发人员，则需要学习SQL编写程序访问MySQL。

> 翻译自: [https://www.thoughtco.com/use-sql-command-2693990][https_www.thoughtco.com_use-sql-command-2693990]

数据库use命令

[MySQL]: https://www.thoughtco.com/understanding-how-sql-databases-work-2693878
[code]: https://www.thoughtco.com/source-code-definition-958200
[Facebook]: https://www.thoughtco.com/who-invented-facebook-1991791
[https_www.thoughtco.com_use-sql-command-2693990]: https://www.thoughtco.com/use-sql-command-2693990