Difference between stored procedures and extended stored procedures

What is the basic difference between 开发者_Go百科SQL Server stored procedures (sp_) and extended stored procedures (xp_)? Why there are extended procedures anyway?

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Extended stored procedures are written in c/c++(I believe anything that can create a DLL in native code), stored procedures are written in T-SQL

extended stored procedures exist because they allow you to do things that you cannot do in T-SQL like running DOS command (xp_cmdshell)

BTW do not name your procs starting with sp_..that is bad practice...see Don't start your procedures with SP_

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An extended stored procedure executes code that is not SQL. It's normally written with external code like in C++.

Using Extended Stored Procedures