将SQL保存在c#源代码或Stored Procs中有哪些优点/缺点?我一直在和一个朋友讨论这个问题,我们正在做一个开源项目(c# ASP。网论坛)。目前,大多数数据库访问都是通过在c#中构建内联SQL并调用SQL Server DB来完成的。所以我在试着确定,对于这个特定的项目,哪个是最好的。

到目前为止,我有:

in Code的优点:

更容易维护-不需要运行SQL脚本来更新查询 更容易移植到另一个DB -没有pros到移植

存储Procs的优点:

性能 安全


当前回答

对于Microsoft SQL Server,您应该尽可能使用存储过程来帮助执行计划缓存和重用。为什么要优化计划重用?因为生成执行计划的成本相当高。

Although the caching and reuse of execution plans for ad-hoc queries has improved significantly in later editions of SQL server (especially 2005 and 2008) there are still far fewer issues with plan reuse when dealing with stored procedures than there are for ad-hoc queries. For example, SQL server will only re-use an execution plan if the plan text matches exactly - right down to comments and white space, for example, if each of the following lines of SQL were to be executed independently, none of them would use the same execution plan:

SELECT MyColumn FROM MyTable WHERE id = @id
select MyColumn from MyTable WHERE id = @id
SELECT MyColumn  FROM MyTable WHERE id = @id
SELECT MyColumn FROM MyTable WHERE id = @id -- "some comment"
SELECT MyColumn FROM MyTable WHERE id = @id -- "some other comment"

除此之外,如果你不显式地指定类型的参数然后有一个好的机会,SQL Server可能出错,例如如果您执行上面的查询与输入4,然后用@ id查询SQL Server将parametrise SMALLINT(或可能是一个非常小的整数),所以如果你然后执行相同的查询@ id的说4000,SQL Server将parametrise INT,而不会重用相同的缓存。

我认为还有其他一些问题,老实说,大多数问题都可以解决——特别是在SQL Server的后续版本中,但是存储过程通常会提供更多的控制。

其他回答

SQL注入攻击呈上升趋势。有人很容易找到这些代码并在你的网站上运行注入攻击。您必须始终始终将查询参数化。最好不要在动态SQL查询上运行exec(@x)。在我看来,使用内联SQL并不是一个好主意。

有些人认为,存储过程很麻烦,因为它们是另一组需要与代码分开维护的项。但是它们是可重用的,如果你在查询中发现了一个错误,你可以在不重新编译的情况下修复它们。

CON

我发现在存储过程中进行大量的处理会使您的DB服务器在扩展您的行为时成为一个单一的不灵活点。

然而,如果您有多个服务器运行您的代码,那么在您的程序中进行所有这些处理而不是sql-server,可能会允许您进行更多的扩展。当然,这并不适用于只进行正常获取或更新的存储procs,而是适用于执行更多处理(如在数据集上循环)的存储procs。

PROS

Performance for what it may be worth (avoids query parsing by DB driver / plan recreation etc) Data manipulation is not embedded in the C/C++/C# code which means I have less low level code to look through. SQL is less verbose and easier to look through when listed separately. Due to the separation folks are able to find and reuse SQL code much easier. Its easier to change things when schema changes - you just have to give the same output to the code and it will work just fine Easier to port to a different database. I can list individual permissions on my stored procedures and control access at that level too. I can profile my data query/ persistence code separate from my data transformation code. I can implement changeable conditions in my stored procedure and it would be easy to customize at a customer site. It becomes easier to use some automated tools to convert my schema and statements together rather than when it is embedded inside my code where I would have to hunt them down. Ensuring best practices for data access is easier when you have all your data access code inside a single file - I can check for queries that access the non performant table or that which uses a higher level of serialization or select *'s in the code etc. It becomes easier to find schema changes / data manipulation logic changes when all of it is listed in one file. It becomes easier to do search and replace edits on SQL when they are in the same place e.g. change / add transaction isolation statements for all stored procs. I and the DBA guy find that having a separate SQL file is easier / convenient when the DBA has to review my SQL stuff. Lastly you don't have to worry about SQL injection attacks because some lazy member of your team did not use parametrized queries when using embedded sqls.

我更喜欢把它们保存在代码中(使用ORM,而不是内联或特别),这样它们就可以被源代码控制覆盖,而不必保存.sql文件。

此外,存储过程本身并不更安全。使用sproc可以像使用内联一样轻松地编写糟糕的查询。参数化内联查询与sproc一样安全。

存储过程的优先级,因为: 在系统运行时修复一些生产中与数据相关的问题(这对我来说是第一个) - DB和程序之间清晰的契约定义(清晰的关注点分离) -更好的可移植性到不同的DB供应商(如果写得好,代码更改通常只在SP端)。 -更好地进行性能调优

缺点:WHERE子句在使用条件上有很大的变化,需要高性能。

我们在Oracle数据库中使用存储过程。我们也使用Subversion。所有存储过程都被创建为.pkb & .pks文件并保存在Subversion中。我以前做过内嵌SQL,这很痛苦!我更喜欢我们在这里的方式。创建和测试新的存储过程比在代码中执行要容易得多。

特蕾莎