Views Vs Queries
Jul 20, 2005
Hello:
I am new to T-SQL programing, and relativly new to SQL statements in
general, although I have a good understanding of database theory. I'm a
little confused as to the fundamental differences between a view and a
query, or rather, when it is more appropriate to use one vs. the other.
It seems to me that most select queries can be implemented as views, and I
can't see the downside to doing so.
I have a rather complicated database structure in terms of the relationships
between various tables, and to get the information that I need into the user
interface forms I have to use a number of nested queries (first to combine
tables together that have been normalized to place the related info in a
single table, then next to extract only the info that I require. In some
cases I would need a 3 level deep nested query to get to what I need. By
implementing the first step, that of combing the normalized tables back into
a single table as a view, it seems to me that I've completed the first step
at the database level, thus making my queries or stored procedures easier to
implement.
I would appreciate any comments which can help me to decide when it is or is
not appropriate to use a view in these circumstances. I should point out
that I don't plan on using the views as part of action queries since they
are made up of multiple tables, I'm primarily interested in using them to
output data which has been consiolidated from multiple tables.
Thanks in advance to any and all who take the time to reply.
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Nov 23, 2007
Hello all,
I'm looking for a best practice.
Let's say you have a report that contains out of 3 queries.
How are you going to create the report and why?
1. Just use "select * from table where p1= value" in your report
2. Save the query in your db as a view and use the view in your report
3. Create a procedure that contains all 3 queries. And use the procedure with some parameters in your report?
Kr
Karel.
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Oct 29, 2007
I just started a new job and 1st time on sql server, how can i print list of queries, tables, views, stored procedures and functions?
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May 13, 2014
Is there an easy way to convert Access Queries to SQL Views without doing it manually?I have used the Databse tool to migrate tables, but cannot see to find something similiar for queries.
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Apr 3, 2006
Fellow database developers,I would like to draw on your experience with views. I have a databasethat includes many views. Sometimes, views contains other views, andthose views in turn may contain views. In fact, I have some views inmy database that are a product of nested views of up to 6 levels deep!The reason we did this was.1. Object-oriented in nature. Makes it easy to work with them.2. Changing an underlying view (adding new fields, removing etc),automatically the higher up views inherit this new information. Thismake maintenance very easy.3. These nested views are only ever used for the reporting side of ourapplication, not for the day-to-day database use by the application.We use Crystal Reports and Crystal is smart enough (can't believe Ijust said that about Crystal) to only pull back the fields that arebeing accessed by the report. In other words, Crystal will issue aSelect field1, field2, field3 from ReportingView Where .... eventhough "ReportingView" contains a long list of fields.Problems I can see.1. Parent views generally use "Select * From childview". This meansthat we have to execute a "sp_refreshview" command against all viewswhenever child views are altered.2. Parent views return a lot of information that isn't necessarilyused.3. Makes it harder to track down exactly where the information iscoming from. You have to drill right through to the child view to seethe raw table joins etc.Does anyone have any comments on this database design? I would love tohear your opinions and tales from the trenches.Best regards,Rod.
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Sep 6, 2007
Which is more efficient? One large view that joins >=10 tables, or a few smaller views that join only the tables needed for individual pages?
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Jun 28, 2007
Hello.
Newbie here. I've only been using SQL for about a year now and have some minor questions about sql objects that reference other objects.
We have some views which reference other views in the joins. I will call one the primary view and the one being referenced in the joins as the secondary view.
Recently we made changes to the secondary view.
After which the primary views which referenced it would not work because of this change and had to be 'refreshed' by using drop/create scripts which essentially just dropped it and recreated the exact same view. I do not recall the exact error message that was returned other than it seemed to suggest that it could no longer see the secondary view since it had been changed. Nothing in the primary view was changed in any way, just the secondary.
Some here where I work have suggested off hand that this was a recompile of the primary view because the contents of the secondary changed.
My questions are:
1. Exactly why did this happen and is there a proper name for it when it does?
2. The same problem does not seem to occur when we have stored procedures referencing views in the joins which had just been changed. Why is that?
Thanks for any help on the matter. I greatly appreciate it.
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Feb 22, 2007
Hello,
to make a report easier I'm developing it using a view of joined views of joined views.
Is there any significant performance penalty as opposed to just having one big select?
Cheers.
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Mar 14, 2006
Hello There,I'm trying to create a view that has calculations dependent oncalculations, where the problem resides is that each time I make acalculation I must create an intermediate view so I can reference aprevious calculation.for example lets say I have my_table that has columns a & b. now I wanta view that has a & b, c = a + b, and d = c + 1.this is grossly simplified, the calculations I actually use are fairlycomplex and copying / pasting them is out of the question.so what I have is my_view_a which makes column c, and my my_view_finalwhich makes column d (however, in my real application I have 5 of theseviews, a/b/c/d/e/)is there anyway I can consolidate all these views into one? I wasthinking of using a stored procedure with temp tables or somethingalong those lines.I just which I can use the aliases that I create for c in d in onestep.any insight would be greatly appreciated.
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Jul 20, 2005
HelloWhen I use a PreparedStatement (in jdbc) with the following query:SELECT store_groups_idFROM store_groupsWHERE store_groups_id IS NOT NULLAND type = ?ORDER BY group_nameIt takes a significantly longer time to run (the time it takes forexecuteQuery() to return ) than if I useSELECT store_groups_idFROM store_groupsWHERE store_groups_id IS NOT NULLAND type = 'M'ORDER BY group_nameAfter tracing the problem down, it appears that this is not preciselya java issue, but rather has to do with the underlying cost of runningparameterized queries.When I open up MS Enterprise Manager and type the same query in - italso takes far longer for the parameterized query to run when I usethe version of the query with bind (?) parameters.This only happens when the table in question is large - I am seeingthis behaviour for a table with > 1,000,000 records. It doesn't makesense to me why a parameterized query would run SLOWER than acompletely ad-hoc query when it is supposed to be more efficient.Furthermore, if one were to say that the reason for this behaviour isthat the query is first getting compliled and then the parameters aregetting sent over - thus resulting in a longer percieved executiontime - I would respond that if this were the case then A) it shouldn'tbe any different if it were run against a large or small table B) thisperformance hit should only be experienced the first time that thequery is run C) the performance hit should only be 2x the time for thenon-parameterized query takes to run - the difference in response timeis more like 4-10 times the time it takes for the non parameterizedversion to run!!!Is this a sql-server specific problem or something that would pertainto other databases as well? I there something about the coorect use ofbind parameters that I overall don't understand?If I can provide some hints in Java then this would be great..otherwise, do I need to turn/off certain settings on the databaseitself?If nothing else works, I will have to either find or write a wrapperaround the Statement object that acts like a prepared statement but inreality sends regular Statement objects to the JDBC driver. I wouldthen put some inteligence in the database layer for deciding whetherto use this special -hack- object or a regular prepared statementdepending on the expected overhead. (Obviously this logic would onlybe written in once place.. etc.. IoC.. ) HOWEVER, I would desperatelywant to avoid doing this.Please help :)
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Apr 15, 2008
Hi everyone, I have a problem like this . I have tables Coursegroupcode, which has groupname, codeI have Courses That has Coursename, its code(group code),Term, Course Number Enrollment table which has Foreign keys Term,Course NUmber , SSN I need to get a view like thisI should list all the coursecodes and people enrolled for each course code for selected terms Course Table Primary keys(TERM,COUSE Number)Enrollment Table(Foreign keys) TERM ,COURSE NUMBER, SSNplease help
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Apr 7, 2005
Hi!
I need to know if i can build an aspx file on top of an sql view? I
can only see my tables when i connect to the database....
Collette.
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Oct 18, 2005
Can SQL Views insert to the tables they are created from?I have a database that is not well structured. It has a lot of redundency. What I want to do is create a SQL View that brings in all the data I need and have my application use that new SQL View instead of the data tables. Then I want to be able to insert new information to a SQL View that actualy gets inserted into the tables that the SQL Viewer is created from.Can this be done?Does this make any sense?
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Mar 26, 2001
I have a query which unions the four select statements.....
the select statements are joined with other tables and views.....
When i execute the query i get ODBC timeout error........
But the strange thing is that if i execute the view individually once and again execute the query it works fine.......and later it justs works fine....
Can anyone tell why is it like that.......
Thanks,
Sajai.
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May 23, 2000
Is there a performance hit running a sp against a view versus a base table. The view just excludes
several of the records based on some criteria, and all the data I will be retreiving is included in
the view. Or should I just stick my criteria in the SP to exclude the data?
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Jun 19, 2000
Is there a way to imbed "iif"-like logic in a SQL view? "case when" works in regular queries, but apparently is not supported in views...
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Aug 14, 2002
I have some rather complex views to work with. Do they slow you down? Would it be better to move a view into a stored procedure? Is there any difference between these three solutions?
<B>1.Using views:</b>
Create view X
As
Select Col1, Col2, Col3 from Table1
Go
Create view Y
As
Select Col1, Col2, Col3 from Table2
Go
Create proc Z
As
Select X.Col2, X.Col3, Y.Col2, Y.Col3
From X inner join Y on X.Col1 = X.Col1
GO
<b>2.Using just a stored proc:</b>
Create proc Z
As
Select X.Col2, X.Col3, Y.Col2, Y.Col3
from
(Select Col1, Col2, Col3 from Table1) X inner join
(Select Col1, Col2, Col3 from Table2) Y on X.Col1 = Y.Col1
<b>.Joining tables</b>
Create proc Z
As
Select Table1.Col2, Table1.Col3, Table2.Col1, Table2.Col3
FromTable1 inner join Table2 on Table1.Col1 = Table2.Col1
go
Thank you!
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Aug 1, 2001
I am struggling with setting up views in SQL Server 7.0 and 2000. What types of views are available.
I have one database with 112 tables and 2308 fields.
Thanks in Advance
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Jun 9, 2004
I have created a database connected to a GUI using VB 6.0. When editing the views from the front end, do the tables also get updated
Thanks
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Aug 17, 2004
Hi,
Is there a way to create a view with read only option. i.e the view should not allow the user to perform insert, update or delete action on it.
Please advise,
Thanks,
Sam
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Dec 23, 2004
Is there any kind of lock on a view in ms sql database?
what happens if one of my users is looking at the view and another one is adding something to the database?
Thanks.
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Sep 26, 2005
My First time building "Views" in SQL...... I'm trying to figure out how to return a 1 instead of a two when I Count the number of records that return inn my view.
here's what I have;
SELECT TOP 100 PERCENT dbo.tbl_ProcTimesheet.idCalendar, dbo.tbl_ProcTimesheet.erNum, dbo.tbl_ProcTimesheet.PayDate,
COUNT(dbo.tbl_ProcTimesheet.TransAmt) AS Shifts, dbo.tbl_ProcTimesheet.[Employee Number], dbo.tbl_ProcTimesheet.YCode,
dbo.tbl_ProcTimesheet.XCode, dbo.tbl_ProcTimesheet.ZCode, dbo.tbl_ProcTimesheet.eeLink
FROM dbo.tbl_ProcTimesheet INNER JOIN
dbo.tbl_SysVarRestEeShiftPayCodes ON dbo.tbl_ProcTimesheet.Code = dbo.tbl_SysVarRestEeShiftPayCodes.PayCode INNER JOIN
dbo.tbl_SysVarRestEeShiftRules ON dbo.tbl_ProcTimesheet.YCode = dbo.tbl_SysVarRestEeShiftRules.YCode AND
dbo.tbl_ProcTimesheet.ZCode = dbo.tbl_SysVarRestEeShiftRules.ZCode
WHERE (dbo.tbl_ProcTimesheet.Sequence <> N'0') AND (dbo.tbl_ProcTimesheet.Week < 3)
GROUP BY dbo.tbl_ProcTimesheet.idCalendar, dbo.tbl_ProcTimesheet.erNum, dbo.tbl_ProcTimesheet.PayDate, dbo.tbl_ProcTimesheet.TransAmt,
dbo.tbl_SysVarRestEeShiftRules.DailyHours, dbo.tbl_ProcTimesheet.[Employee Number], dbo.tbl_ProcTimesheet.XCode,
dbo.tbl_ProcTimesheet.YCode, dbo.tbl_ProcTimesheet.ZCode, dbo.tbl_ProcTimesheet.eeLink, dbo.tbl_ProcTimesheet.Sequence,
dbo.tbl_ProcTimesheet.Week
HAVING ('IIf' > '1,1,0') AND ('if' > '1,1') AND (dbo.tbl_ProcTimesheet.erNum LIKE N'5648 ') AND (SUM(dbo.tbl_ProcTimesheet.TransAmt)
>= dbo.tbl_SysVarRestEeShiftRules.DailyHours) AND (dbo.tbl_ProcTimesheet.PayDate = CONVERT(DATETIME, '2005-09-06 00:00:00', 102)) AND
(COUNT(dbo.tbl_ProcTimesheet.TransAmt) > 0)
ORDER BY dbo.tbl_ProcTimesheet.PayDate, dbo.tbl_ProcTimesheet.[Employee Number]
When it counts shifts, I only want to return a maximum of i, as in either you had a shoft that day, or not. I gave up trying to figure out the "IF" string in SQL, and for the life of me I can not figure this out.
Does anyone know a good site with info on how to construct an SQL View?
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Jun 1, 2004
Hi,
I'm creating a stored procedure that will Drop all views when executed, this is what i have...
DECLARE crsViews CURSOR FOR
SELECT
name AS strViews
FROM
__________ <what do i put here?
WHERE
type ='U'
AND NAME LIKE'V%'
Thanks for any help!
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Apr 21, 2008
MS SQL Server 2005
What happens if 2 or more users use the same View at the same time or while other user is using it, normally from Crystal Reports 10
It rebuilds again? Or?
Thanks
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Apr 25, 2008
Hi,
I have a SQL server: SQL2005
2 databases
db_repl: contains replicated data from mainframe
db_my: my database
db_my.vwRepl_WorkOrders: Select 1,2,3 from db_repl.dbo.WorkOrders
db_my.vwWorkOrdersOpen: select 1,2,3 from db_my.vwRepl_WorkOrders where Status=1
which approach is more optimal to do in order to find open work orders from Texas:
[select 1,2,3
from db_repl.dbo.workOrders where Status=1 and State=1
or
select 1,2,3
from db_my.vwWorkOrdersOpenwhere where State=1]
Is it best practice to use 'subviews' that acess db_repl directly or acess views in my_db that acess db_repl (2 hops or more if views call other views that call other views) Answer might be the obvious but just in case I am missing something here .
Thanks!
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Apr 17, 2007
Can someone tell me when I would get an error like the one below:
"Update or insert of view or function failed because it contains a derived or constant field."
Here is how I create a VIEW
CREATE VIEW vSample
AS
SELECT ilm.ITEM_ID,
CAST (ilm.CURRENT_QUANTITY AS INT) CURRENT_QUANTITY
FROM SAMPLE_1 AS ilm INNER_JOIN SAMPLE_2 AS ilm2
on ilm.ID = ilm2.ID
Now, I am trying to update data using the view
UPDATE [vSample] SET [CURRENT_QUANTITY] = 598.00 WHERE (1 = 1)
I have tried casting the number 598.00 as int and no luck.
Can someone please help or guide me on this problem?
Thanks,
Javid
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Nov 6, 2007
Hello,
I am kind of new to using views. What types of queries can i use with view (i.e. select, insert, update, delete) in mssql 2000?
DigitalSolvers
Yahoo: DigitalSolvers
MSN Live: lew26@msn.com
Skype: DigitalSolvers
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Nov 17, 2007
I've created views ProductsSold that will list all the products- ProductID and quantity, that were ordered (OrderDate) in last twenty four hours between getdate()-1 and getdate().
create view ProductsSold
as
select orderdetails.ProductID, orderdetails.OrderQty, orders.OrderDate
from OrderDetails inner join Orders
on OrderDetails.salesOrderID = Orders.salesOrderID
where OrderDate > dateadd(d, -1, getdate()) and OrderDate < getdate()
i just wonder if there is a more simpler way to query it?
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Sep 11, 2006
Hi all,We have a big table connected to a web server, and I want the number ofrows to be limited that get returned.So I could do something like this:select top 10 *from objectorder by codeI then realised looking at the help file, because the "order by" clauseis set the SQL Server has to build the complete dataset, do the orderby and then filter it to the first ten rows.So I was wondering if I put the query into a view like so :create view vw_object asselect top 10 *from objectThen ran the query like so:select *from vw_objectorder by codewould the SQL server just get the top 10 rows from the view first, thenapply other order by on it afterwards?
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Jul 20, 2005
I've searched for information on this but so far have not been able tofind any advice.We have several databases running on SQL Server 7.0 that areessentially identical in structure but are used for different data.There are several tables that are identical in all databases.Currently, we make updates to those tables in one database andpropogate the new versions of those tables to the other databases.The maintenance to keep after this is somewhat problematic in that theuser, or dba, has to initiate some action to apply the update to alltables anytime a change is made. An idea I have to simplify thisprocess is create views that access the data in a central location.I would create a database for these shared tables, and replace thetables in each individual database with a view of the same name. Theother nice thing about this solution is it is transparent toapplications that rely on this data. I contemplated using the shareddatabase by making code changes to change all the references to thosetables to DB..table, but that would take considerable man hours. Cananyone give me a reason why this would not be a good idea? Thanks.
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Apr 26, 2006
I am supposing that SQL Mobile 2005 does not support views in its database? It is odd that all development tools show the tab of Views, but I cannot seem to find how someone would create one there. Is there a reference someone can point me to, or just reply to the forum to set me straight.
Thanks.
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Oct 25, 2006
Hi
In acces i have make a view witkh this code
<> #15:30:00#
How can i write this in a view on the sql sever
I have try with <> '15:30:00'
But it dosn't work , my field i a datetime( maybe i shal change that??
Hope someone can help
Regards
alvin
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Feb 8, 2008
Hello... how to update from Views.?
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