Question

I am confused about a few points:

1. What is the difference between a stored procedure and a view?

2. When should I use stored procedures, and when should I use views, in SQL Server?

3. Do views allow the creation of dynamic queries where we can pass parameters?

4. Which one is the fastest, and on what basis is one faster than the other?

5. Do views or stored procedures allocate memory permanently?

6. What does it mean if someone says that views create a virtual table, while procedures create a materials table?

Please let me know about more points, if there are any.

Answer 1

A view represents a virtual table. You can join multiple tables in a view and use the view to present the data as if the data were coming from a single table.

A stored procedure uses parameters to do a function… whether it is updating and inserting data, or returning single values or data sets.

Creating Views and Stored Procedures – has some information from Microsoft as to when and why to use each.

Say I have two tables:

• tbl_user, with columns: user_id, user_name, user_pw
• tbl_profile, with columns: profile_id, user_id, profile_description

So, if I find myself querying from those tables A LOT… instead of doing the join in EVERY piece of SQL, I would define a view like:

CREATE VIEW vw_user_profile
AS
  SELECT A.user_id, B.profile_description
  FROM tbl_user A LEFT JOIN tbl_profile B ON A.user_id = b.user_id
GO

Thus, if I want to query profile_description by user_id in the future, all I have to do is:

SELECT profile_description FROM vw_user_profile WHERE user_id = @ID

That code could be used in a stored procedure like:

CREATE PROCEDURE dbo.getDesc
    @ID int
AS
BEGIN
    SELECT profile_description FROM vw_user_profile WHERE user_id = @ID
END
GO

So, later on, I can call:

dbo.getDesc 25

and I will get the description for user_id 25, where the 25 is your parameter.

There is obviously a lot more detail, this is just the basic idea.