blocks|key|945927|text|使用触发器。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|945928|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

blocks|key|157834|text|泛化该表以保存“设置”，并使其成为键/值对|type|unstyled|depth|inlineStyleRanges|entityRanges|data|157835|CREATE+TABLE+Settings+(Key+nvarchar(max),+Value+nvarchar(max))|code-block|syntax|javascript|157836|然后在Key上建立唯一的索引。|157837|CREATE+UNIQUE+INDEX+SettingsIDX+ON+Settings+(Key)|157838|这将创建一个具有唯一键值对的表，其中一个可以是Version。|157839|INSERT+INTO+Settings+(Key,+Value)+VALUES+('Version','1');|157840|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Generalize the table to hold "settings" and make it a key/value pair

<pre><code>CREATE TABLE Settings (Key nvarchar(max), Value nvarchar(max))
</code></pre>

Then make a unique index on Key.

<pre><code>CREATE UNIQUE INDEX SettingsIDX ON Settings (Key)
</code></pre>

That will create a table with unique key value pairs, one of which can be Version.

<pre><code>INSERT INTO Settings (Key, Value) VALUES ('Version','1');
</code></pre>

blocks|key|4221062|text|你可以使用Joe+Celko的default%2Bprimary%2Bcheck技术：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4221063|create+table+database_version+(

++lock+char(1)+primary+key+default+'x'+check+(lock='x'),
++major_version_number+int+NOT+NULL,
++minor_version_number+int+NOT+NULL,
++revision_number+int+NOT+NULL
);|code-block|syntax|javascript|4221064|使用它进行Fiddle|offset|length|4221065|entityMap|0|LINK|mutability|MUTABLE|url|http://sqlfiddle.com/#!3/aeb48/3^0|0|0|5|6|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

You can use Joe Celko's default+primary+check technique:

<pre><code>create table database_version (

 lock char(1) primary key default 'x' check (lock='x'),
 major_version_number int NOT NULL,
 minor_version_number int NOT NULL,
 revision_number int NOT NULL
);
</code></pre>

<a href="http://sqlfiddle.com/#!3/aeb48/3" rel="nofollow">Fiddle</a> with it

blocks|key|4220878|text|不用谢。您可以简单地向该表添加另一个升序列(date、id等)，然后按另一列的降序对查询进行排序，并将结果限制为一行：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4220879|SELECT+v.version+FROM+version+v+ORDER+by+v.date+DESC+LIMIT+1;|code-block|syntax|javascript|4220880|这样，您甚至可以获得每个版本何时到达的历史记录。|4220881|编辑：|4220882|上面的sql查询在SQL+Server上不起作用，因为它不支持LIMIT语句。人们将不得不绕过这个缺陷，可能正如本"All+Things+SQL+Server"+blog+entry所描述的那样。|offset|length|4220883|entityMap|0|LINK|mutability|MUTABLE|url|http://blogs.msdn.com/sqlserver/archive/2006/10/25/limit-in-sql-server.aspx^0|0|0|0|0|1L|Y|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|10|8|@]|9|@$M|11|N|12|1|13]]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

Not at all. You can simply add another, ascending column to that table (date, id, whatever), and then order the query by that other column descendingly and limit the result to 1 row:

<pre><code>SELECT v.version FROM version v ORDER by v.date DESC LIMIT 1;
</code></pre>

This way you even get a history of when each version was reached. 

Edit:

The above sql query wouldn't work on SQL Server since it doesn't support the LIMIT statement. One would have to circumvent that deficiency, possibly as described in this <a href="http://blogs.msdn.com/sqlserver/archive/2006/10/25/limit-in-sql-server.aspx" rel="nofollow noreferrer">"All Things SQL Server" blog entry</a>.

blocks|key|3374687|text|根据你对其他回复的评论，似乎是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3374688|3374689|您不希望用户只修改该值。|ordered-list-item|3374690|您只希望返回一个值。|3374691|该值是静态的，并且是脚本化的。|3374692|3374693|那么，我可以建议您编写一个返回静态值的函数吗？因为无论如何您都必须编写一个更新版本号的脚本，所以在更新数据库时，您只需在脚本中删除并重新创建该函数即可。|3374694|这样做的优点是可以从视图或过程中使用，而且因为函数的返回值是只读的，所以不能修改它(如果不修改函数)。|3374695|编辑：您也不必担心将表限制为一行的复杂解决方案。|offset|length|style|BOLD|3374696|这只是个建议。|3374697|entityMap^0|0|0|0|0|0|0|0|0|0|2|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|10|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|12|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@$Q|17|R|18|S|T]]|9|@]|A|$]]|$1|U|3|V|5|6|7|19|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|X|$]]

Based on your comments to other responses, it seems that:

<ol>
<li>You don't want users to just modify the value.</li>
<li>You only ever want one value returned.</li>
<li>The value is static, and scripted.</li>
</ol>

So, might I suggest that you script a function that returns the static value? Since you'll have to script an update to the version number anyway, you'll simply drop and recreate the function in your script when you update the database.

This has the advantage of being usable from a view or a procedure, and since a function's return value is read-only, it can't be modified (without modifying the function).

EDIT: You also wouldn't have to worry about convoluted solutions for keeping a table constrained to one row.

Just a suggestion.

blocks|key|4221029|text|为数据库保留一个版本号是完全有意义的。但是，我更喜欢有一个版本表，它可以包含多个行，其中包含版本号、更新发生的时间和执行升级的用户的字段。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4221030|这样，您就可以知道哪些升级脚本已经运行，并可以很容易地查看它们是否已经失序运行。|4221031|当您想要读取当前版本号时，您可以只读取最近的记录。|4221032|如果您只存储了一条记录，则可以知道是否遗漏了脚本。如果你想变得更聪明，你可以在你的升级脚本中添加检查，这样它们就不会运行，除非数据库的前一个版本是正确的。|4221033|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Keeping a version number for the database makes total sense. However I prefer to have a Version table that can contain multiple rows with fields for the version number, the time the update occured and the user that performed the upgrade.

That way you know which upgrade scripts have been run and can easily see if they have been run out of sequence. 

When you want to read the current version number you can just read the most recent record.

If you only store one record you have know way of knowing if a script has been missed out. If you want to be really clever you can put checks in you upgrade scripts so they won't run unless the previous version of the database is correct.

blocks|key|3374635|text|通过创建一个允许的原始行作为数据库初始化脚本的一部分，并(也在该脚本中)删除所有登录对该表的插入权限(只允许更新)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3374636|您可能还想禁止删除操作...|3374637|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

By creating the one allowable original row as part of the database initialization script, and (also in that script) removing Insert permissions to that table for all logins (Only Updates will be allowed)

You might also want to disallow deletes as well...

We have a database (SQL Server 2005) which we would like to get under source control. As part of that we are going to have a version table to store the current version number of the database. Is there a way to limit that table to only holding one row? Or is storing the version number in a table a bad idea? 

Ended up using this approach:

<pre><code>CREATE TABLE [dbo].[DatabaseVersion]
 (
 [MajorVersionNumber] [int] NOT NULL,
 [MinorVersionNumber] [int] NOT NULL,
 [RevisionNumber] [int] NOT NULL
 )
GO

Insert DataBaseVersion (MajorVersionNumber, MinorVersionNumber, RevisionNumber) values (0, 0, 0)
GO

CREATE TRIGGER DataBaseVersion_Prevent_Delete
ON DataBaseVersion INSTEAD OF DELETE
AS
BEGIN
 RAISERROR ('DatabaseVersion must always have one Row. (source = INSTEAD OF DELETE)', 16, 1) 
END
GO

CREATE TRIGGER DataBaseVersion_Prevent_Insert
ON DataBaseVersion INSTEAD OF INSERT
AS
BEGIN
 RAISERROR ('DatabaseVersion must always have one Row. (source = INSTEAD OF INSERT)', 16, 1) 
END
GO
</code></pre>

Can you limit the number of rows in a (database) table?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

教程

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云智能顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

聚焦“写作效率、视觉美观与运行性能”三方面进行全面升级，为您提供更高效、稳定的创作环境

社区富文本&Markdown编辑器全新改版上线，欢迎大家体验!

诚挚邀请您参与本次调研，分享您的真实使用感受与建议。您的反馈至关重要，感谢您的支持与参与！

社区新版编辑器体验调研

我们有一个数据库(SQL Server2005)，我们希望将其置于源代码管理之下。作为其中的一部分，我们将有一个版本表来存储数据库的当前版本号。有没有办法将该表限制为只包含一行？或者将版本号存储在表中是不是一个好主意？最终使用了这种方法：CREATE TABLE [dbo].[DatabaseVersion]    (        [MajorVersionNumber] [int]  NOT 

问你能限制(数据库)表中的行数吗？
EN

回答 7

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问你能限制(数据库)表中的行数吗？EN

回答 7

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问你能限制(数据库)表中的行数吗？
EN