SQL Server的隐藏特性

SQL Server有哪些隐藏特性?

例如，没有文档的系统存储过程，做一些非常有用但没有足够文档的事情的技巧?

答案

感谢大家的精彩回答!

存储过程

sp_msforeachtable: Runs a command with '?' replaced with each table name (v6.5 and up) sp_msforeachdb: Runs a command with '?' replaced with each database name (v7 and up) sp_who2: just like sp_who, but with a lot more info for troubleshooting blocks (v7 and up) sp_helptext: If you want the code of a stored procedure, view & UDF sp_tables: return a list of all tables and views of database in scope. sp_stored_procedures: return a list of all stored procedures xp_sscanf: Reads data from the string into the argument locations specified by each format argument. xp_fixeddrives:: Find the fixed drive with largest free space sp_help: If you want to know the table structure, indexes and constraints of a table. Also views and UDFs. Shortcut is Alt+F1

片段

Returning rows in random order All database User Objects by Last Modified Date Return Date Only Find records which date falls somewhere inside the current week. Find records which date occurred last week. Returns the date for the beginning of the current week. Returns the date for the beginning of last week. See the text of a procedure that has been deployed to a server Drop all connections to the database Table Checksum Row Checksum Drop all the procedures in a database Re-map the login Ids correctly after restore Call Stored Procedures from an INSERT statement Find Procedures By Keyword Drop all the procedures in a database Query the transaction log for a database programmatically.

功能

哈希字节（） EncryptByKey 枢轴命令

Misc

Connection String extras TableDiff.exe Triggers for Logon Events (New in Service Pack 2) Boosting performance with persisted-computed-columns (pcc). DEFAULT_SCHEMA setting in sys.database_principles Forced Parameterization Vardecimal Storage Format Figuring out the most popular queries in seconds Scalable Shared Databases Table/Stored Procedure Filter feature in SQL Management Studio Trace flags Number after a GO repeats the batch Security using schemas Encryption using built in encryption functions, views and base tables with triggers

当前回答

Vardecimal存储格式

SQL Server 2005为数字和十进制数据类型添加了一种新的存储格式，称为vardecimal。Vardecimal是十进制类型的一种变长表示，可以在行的每个实例中保存未使用的字节。如果十进制定义很大(如decimal(38,6))，但存储的值很小(如0.0)，或者有大量重复值，或者数据填充稀疏，则可以节省最多的时间。

Link

2008-09-29 17:02:46

其他回答

表校验和

Select CheckSum_Agg(Binary_CheckSum(*)) From Table With (NOLOCK)

行校验和

Select CheckSum_Agg(Binary_CheckSum(*)) From Table With (NOLOCK) Where Column = Value

2008-09-23 15:56:53

在恢复数据库用于测试或其他用途时非常有用。正确地重新映射登录ID:

EXEC sp_change_users_login 'Auto_Fix', 'Mary', NULL, 'B3r12-36'

2008-09-23 17:56:07

存储过程的一个技巧是可以从INSERT语句调用它们。当我在SQL Server数据库上工作时，我发现这非常有用。

CREATE TABLE #toto (v1 int, v2 int, v3 char(4), status char(6))
INSERT #toto (v1, v2, v3, status) EXEC dbo.sp_fulubulu(sp_param1)
SELECT * FROM #toto
DROP TABLE #toto

2008-09-26 08:58:55

可伸缩的共享数据库

通过可伸缩共享数据库，可以在普通机器上挂载相同的物理驱动器，并允许多个SQL Server 2005实例使用同一组数据文件。这种设置不需要为每个SQL Server实例复制存储，并且允许多个SQL Server实例具有额外的处理能力，这些实例具有自己的本地资源，如cpu、内存、tempdb和其他潜在的本地数据库。

Link

2008-09-29 17:03:32

强制参数化

参数化允许SQL Server利用查询计划重用，并避免后续执行类似查询时的编译和优化开销。然而，由于这样或那样的原因，仍然有许多应用程序存在特殊的查询编译开销。对于查询编译次数较多、降低CPU利用率和响应时间对工作负载至关重要的情况，强制参数化可以提供帮助。

Link

2008-09-29 17:02:20

SQL Server的隐藏特性

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