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As long as each of the tables involved have a unique index or PK constraint (preferably clustered) specified on the key column the query should perform well. I would say that the problem comes with the maintenance effort required to add subclassed tables to all of your queries. I try not to overuse this design for that reason, rather than for performance.
An alternative common design that may perform better would be to merge all of the sub-classed tables into the ancestor table.
If you are worried about performance and encapsulation then you might consider using a hybrid of the two designs - so that the most commonly-used information is merged into the ancestor table, with the sub-classed tables only required in exceptional cases.
Like many design decisions - there is no right or wrong answer
Andy
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I totally agree about the maintenance issue that arises from having so many subclassed tables in such a query. I began to explore a different path and ended up not going with huge query that you suggested. I'm trying my "bestest" to do an n-tier approach and that huge query didn't fit right with what I had. Though who knows if I'm doing it close to right. lol
Thanks again.
Keith
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hi all
I have an table
CREATE TABLE [MultyItemsTab] (
[MultyId] [int] IDENTITY (0, 1) NOT NULL ,
[SingleId] [int] NOT NULL ,
CONSTRAINT [PK_MultyItemsTab] PRIMARY KEY
(
[MultyId],
[SingleId]
) ON [PRIMARY] ,
...
)
GO
And i want to save into one xml-based data
<br />
...<br />
set @txt = '<ROOT> <Style SingleId="0"/><Style SingleId="1"/> </ROOT>'<br />
<br />
EXEC sp_xml_preparedocument @idoc OUTPUT, @txt<br />
<br />
insert into MultyItemsTab select * from openxml(@idoc,'/ROOT/Style',0) with (SingleId int)<br />
<br />
...
And as a result in a table added 2 rows;
-----------------
MultyId-------------SingleId
0-------------------0
1-------------------1
But actually i want what MultyId indent not increase when add rows to this table at once.
I mean what desirable result is:
-----------------
MultyId-------------SingleId
0-------------------0
0-------------------1
How i can do this????
THANKS
-- modified at 10:16 Thursday 1st February, 2007
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Calling by the other way:
Is it possible to call a stored procedure WITH PARAM from .net WITHOUT using "AddParams" ? I mean we should be able to call(exec) the SP just like we do in the query analyser. I'd construct the string like "sp_testproc '111','RR',23'". and execute it as nonQuery. Is there any way? please help.
*
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Theoretically you could do this by setting the CommandType to Text and then issue the command directly. I would strongly advise you against doing this however. This is not a good design, and it is certainly not a robust or secure design. By passing in parameters as part of a string, you open yourself right up for Sql Injection attacks.
I cannot see any reason, apart from convenience, why you would do this. Use command parameters - they are much better for your needs.
the last thing I want to see is some pasty-faced geek with skin so pale that it's almost translucent trying to bump parts with a partner - John Simmons / outlaw programmer
Deja View - the feeling that you've seen this post before.
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Any trick of using Select TOP in dataset to datatable. I know that we can have a select TOP in the query but that is currently infeasible in my case since datasource does not support that. Also this is for .NET framework 1.1.
Any clues?
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Hi Deepak,
u can use the following query to select teh datarows in f/w 1.1.
DataRow[] arrDRow = ds.Tables[0].Select("Top 10");
this returns an array of datarows with the criteria specified, which you can manipulate as required.
Let me know if that works.
Regards
Deepali
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Missing operand after 10 operator
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Hi All,
I have a question for you?
I have to pass 7 parameters to the procedure.
for some parameters i am not passing a value.
how to do this?
sivamyneni
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You need to supply defaults for each of your optional parameters:
create procedure MyProc
@Param1 varchar(10) = null,
@Param2 int = null,
@Param3 date = null
as begin
set nocount on
--do stuff
return(0)
end
go
exec MyProc
exec MyProc 'hello', 123, '1 feb 2007'
exec MyProc 'world'
exec MyProc @Param3 = '1 feb 2007' Hope this helps.
Andy
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Hi
I tried that one i am not getting proper result because none of my field contaains null value.so i am not getting the desired.
sivamyneni
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Try this:
If Your procedure is like following:
ALTER PROCEDURE myProcedure<br />
@Param1 int = 0,<br />
@Param2 int = 0, <br />
@Param3 int,<br />
@Param4 int = 0,<br />
@Param5 int = 0, <br />
@Param6 int,<br />
@Param7 int<br />
<br />
<br />
AS<br />
<br />
<br />
-- Procedure code
In order to call it (say, from another sp):
exec myProcedure @Param3 = @PassedParam1, @Param6 = @PassedParam2, @Param7 = @PassedParam3
Note: Initialize parameters in the original procedure if you are not sure, the procedure will get those parameters passed to it. (In the case above, if you will not pass one of the @Param3, @Param6, or @Param7) the error will happen.
Hope that helps.
Sincerely,
Elina
Life is great!!!
Enjoy every moment of it! 
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hi,
i need some help regarding data access from XML sent by web services.
I have a web service that sends out XML as its result, as below:
<?xml version="1.0" encoding="utf-16"?>
<Response webMethodId="GetUserListing">
<SecurityContext sessionId="154oe1upayjpnx55pg1f3r45" />
<Document>
<ArrayOfUsers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<User>
<UserId>32</UserId>
<Name>foxtrot</Name>
<Address>Suite 712</Address>
<Zip>12345</Zip>
< PhoneNumbers>
<string 111-111-1111/>
</PhoneNumbers>
<Emails>
<string>foo@foo.bar</string>
</Emails>
</User>
</ArrayOfUsers>
<TotalRecords>25</TotalRecords>
</Document>
</Response>
In the RDL file, the Query i specify is:
<Query>
<Method Namespace ="http://tempuri.org/" Name = "ProcessRequest" ></Method>
<SoapAction>http://tempuri.org/ProcessRequest</SoapAction>
</Query>
and the result i get is in a single line that says ProcessRequestResult, with the XML specified above in a single line. however, i need the result in a tabular form, which would give me records of different users, one below the other.
if i specify the <ElementPath> element for the query, i do not get any response at all.
The <ElementPath> element i specify is:
<ElementPath>Response{}/SecurityContext{}/Document{}/ArrayOfUser{}/User</ElementPath>
i need urgent help for this and any help would be appreciated.
Thanks in advance
Deepali
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Hi
Can anyone help with an SQL statement im having problems with ?
i want to do something like the below
select date_in, type= CASE date_in
when datepart(hour,date_in) > 12 THEN 'Afternoon'
ELSE 'Morning'
END
from my_table
where date_in >='2007-2-1'
so it will return something like
2007-02-01 08:22:32.663 Morning
2007-02-01 09:22:32.773 Morning
2007-02-01 14:42:32.803 Afternoon
2007-02-01 15:56:32.803 Afternoon
however im getting an error thrown back at me when i try to execute it
Line 2: Incorrect syntax near '>'.
Any ideas ??
thanks
Simon
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correct your query like this
select date_in, type= CASE
when datepart(hour,date_in) > 12 THEN 'Afternoon'
ELSE 'Morning'
END
from my_table
where date_in >='2007-2-1'
Regards,
Sylvester G
Senior Software Engineer
Xoriant Solutions
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You do not have a BEGIN for the END specified below ELSE
Deepali
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CASE has two syntaxes. You can either use it like a C/C++/C# switch or VB Select Case statement, where you specify an expression to be tested against multiple possibilities, or you can use it more like a multi-armed if statement, where you supply boolean expressions - the first one to evaluate to true is then returned.
The syntax for the first is:
CASE expression
WHEN value1 THEN result1
WHEN value2 THEN result2
ELSE defaultresult
END The syntax for the second:
CASE
WHEN booleanexpression1 THEN result1
WHEN booleanexpression2 THEN result2
ELSE defaultresult
END
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Hello,
Is it better to use define data type in sql tables, What is advantage and disadvantage of user define data types ?
Regards,
S Kumar
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I like defined data types. They are a great way to enforce standards. For instance, if I have a need for Name fields throughout the database and they are always going to be 30 characters then it is much better for me to be able to define a name data type and then use this wherever there is a Name field.
the last thing I want to see is some pasty-faced geek with skin so pale that it's almost translucent trying to bump parts with a partner - John Simmons / outlaw programmer
Deja View - the feeling that you've seen this post before.
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Hi John,
Thanks a lot for your reply.
Best Regards,
S Kumar
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Hi,
I've heard that there is an sql helper file which has got all the stuff regarding the connectivity to the databse, like connectio, command objects....
Is there any any sort of refernce/link where i could get that?
Thanks!
Gautham
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Which index is good to apply.clustered or nonclustered?
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It really depends on the situation, as each type of index has its strengths and weaknesses. If you were offering a phone book, for instance, and wanted to have quick retrieval based on the surname then forename, then a clustered index is much better than an ordinary index because there is a great deal of internal sorting going on there. So searching on Smith John would quickly retrieve the Smiths and then fine filter from there to return the Johns.
The downside of the clustered index is the fact that everytime an insert occurs, then significant reordering needs to be done to guarantee that rows are kept adjacent. This means that clustered indexes can become a real performance hit in high-insert tables.
the last thing I want to see is some pasty-faced geek with skin so pale that it's almost translucent trying to bump parts with a partner - John Simmons / outlaw programmer
Deja View - the feeling that you've seen this post before.
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Generally it is best to have a clustered index defined on every SQL Server table - otherwise it is treated as a heap. By default SQL-Server creates clustered indexes for primary keys. The engine contains a specific optimisation that makes it efficient to have a clustered index that is based upon an incrementing identity column.
A clustered index contains the table's data in its leaf nodes, so the records are physically sorted - and so is ideal for "range" scans. The following scenario takes advantage of this:- A "Customer" table has a clustered primary key on "CustId".
- An "Invoice" table has a non-clustered primary key on "InvoiceId", and a unique clustered index on "CustId, InvoiceId".
It is now very efficient to join between the Customer and Invoice tables.
Another technique that may prove useful, is to define a non-clustered index, but include additional columns that you would not normally be searching upon. SQL-Server will automatically use the data from the index (and not attempt to read the table data) if all of the information it requires for a query is located in a suitable index. This is called "covering".
http://www.sql-server-performance.com/tips_performance.asp[^] contains a bunch of articles and tips that you may find useful.
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