Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 12: Stored Procedures
Dropping Sprocs
It doesn’t get much easier than this:
DROP PROC|PROCEDURE [;]
And it’s gone.
Parameterization
A stored procedure gives you some (or in the case of .NET, a lot of) procedural capability and also gives you
a performance boost (more on that later), but it wouldn’t be much help in most circumstances if it couldn’t
accept some data to tell it what to do. For example, it doesn’t do much good to have a spDeleteVendor
stored procedure if we can’t tell it what vendor we want to delete, so we use an input parameter. Likewise,
we often want to get information back out of the sproc — not just one or more recordsets of table data,
but also information that is more direct. An example here might be where we update several records in a
table and we’d like to know just how many we updated. Often, this isn’t easily handed back in recordset
form, so we make use of an output parameter.
From outside the sproc, parameters can be passed in either by position or by reference. From the inside,
it doesn’t matter which way they come in — they are declared the same either way.
Declaring Parameters
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Declaring a parameter requires two to four of these pieces of information:
❑ The name
❑ The data type
❑ The default value
❑ The direction
The syntax is:
@parameter_name [AS] datatype [= default|NULL] [VARYING] [OUTPUT|OUT]
The name has a pretty simple set of rules to it. First, it must start with the @ sign (just like variables do).
Other than that, the rules for naming are pretty much the same as the rules for naming described in
Chapter 1, except that they cannot have embedded spaces.
The data type, much like the name, must be declared just as you would for a variable — with a valid
SQL Server built-in or user-defined data type.
One special thing in declaring the data type is to remember that, when declaring a parameter of type
CURSOR, you must also use the VARYING and OUTPUT options. The use of this type of parameter is
pretty unusual and well outside the scope of this book, but keep it in mind in case you see it in books
online or other documentation and wonder what that’s all about.
Note also that OUTPUT can be abbreviated to OUT.