与DBMS中的DML命令有关的疑问. [英] A doubt related to DML commands in DBMS.

问题描述

大家好，

我们都知道DML命令是DBMS中的数据操作命令.
DML命令:用于数据库表中的数据操作.

Hi all,

We all know that DML commands are Data manipulation commands in DBMS.
DML commands: used for data manipulations in database tables.

SELECT

DELETE

UPDATE

INSERT

为什么将SELECT命令归类为DML?当我们知道它仅用于从数据库表中选择数据而没有涉及数据操作时..
任何原因……??

why the SELECT Command is categorised into DML When We know that it is just used to select data from database table and no data manipulations involved..
ANY REASON......??

推荐答案

大多数开发人员都从DML数据操作语言(删除，插入，更新，尤其是DML)的角度来考虑SQL.选择语句.真正的Select通过与其他表的联接，分组，嵌套的子选择和其他检索功能，提供了很多检索功能.同样，了解主要供应商在遵守SQL''99标准方面的紧密程度非常有启发性.但是有一些变化.正好足以引起互操作性的麻烦.

谢谢.

Most developers think of SQL in terms of the DML-Data Manipulation Language: the Delete, Insert, Update and particularly the Select statements. And truly Select provides a lot of retrieval power with joins to other tables, grouping, nested subselects and other retrieval goodies. Again, it is very instructive to see how closely the major vendors have adhered to the SQL''99 standard; but there are some variations. Just enough to cause a nuisance for interoperability purposes.

Thanks.

你好Ramakrishna Alla，

根据对数据库表的操作，您已经对DML命令进行了很好的分类.

谢谢您分享您的答案...

Hi Ramakrishna Alla,

You have made very good classification of DML commands depending on thier action on database table.

Thank You for Sharing your answer...

实际上Select不是DML的一部分，而是CRUD(C-Create/Insert，R-Read/Select，U-Update，D-Delete )

Select命令属于DRL(数据检索语言)-(它不影响DB的状态(此处状态表示受影响的行数))-因此我们也将Select称为非操作查询.
DML-插入，更新，删除(这三个用于更改数据库状态)我们也将它们称为操作查询.

由
Ramakrishna Alla

Actually Select is not a part of DML but CRUD(C-Create/Insert,R-Read/Select,U-Update,D-Delete)

Select Command is belongs DRL(Data Retreival Language)-(It doesn''t affect on state of DB (here state indicates number of rows affected))-so We also call Select as Non action query.
DML - Insert ,Update, Delete (these three are change the state of database)We also call them as action queries.

By
Ramakrishna Alla

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