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Have you used the Sql Server Configuration Manager like Colin suggested? On my test box, I've opened up the TCP/IP, Named Pipes, and the others. Not sure if this helps out.
John Simmons / outlaw programmer wrote: I've tried the machine name ("earth2") and 127.0.0.1
How about the actual IP of the machine? Not sure about it working with the loopback...
"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon
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Hi all,
Let say I have a table with 100+ columns and millions of rows, and I only need to gather all data in column A and B. Will the second query below perform faster, or no difference whatsoever?
1: SELECT * FROM MyTable
2: SELECT A,B From MyTable
Thanks for any pointers.
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The second query will perform faster because it will use less bandwidth to get the results to the client. The first query will return a large amount of data that is not needed.
Let's say you have one million rows and each of your columns are integers (or 4 bytes on average) that means each row is 400 bytes (if you have 100 colums), which requires 400,000,000 bytes (+ some overhead for the protocol - Call it 400Mb) to get that data to the client.
If you get only the columns you want that is 8 bytes per row which is 8,000,000 for all the million rows (+ some overhead for the protocall - Call it 8Mb).
So, even if you are on a super-duper network 8Mb will transfer faster than 400Mb. And if you have lots of clients that is a lot of network bandwidth being saved.
Upcoming events:
* Glasgow: Mock Objects, SQL Server CLR Integration, Reporting Services, db4o, Dependency Injection with Spring ...
"I wouldn't say boo to a goose. I'm not a coward, I just realise that it would be largely pointless."
My website
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I can see that the second query is definitely faster if I run the queries in SQL Management Studio (I am using SQL Express 2005).
Now, the question is: if I run the query from the code (VC++) like the following pseudo-code:
CADORecordset pRs = CADORecordset(&theApp.m_pDb);
if(pRs.Open(sz, CADORecordset::openQuery))
{
while(!pRs.IsEOF())
{
pRs.GetFieldValue("A", szA);
pRs.GetFieldValue("B", szB);
...
pRs.MoveNext();
}
}Will the first query still use less bandwith? Isn't the data transferred during the GetFieldValue function, so the two queries perform exactly the same?
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Joe Smith IX wrote: Will the first query still use less bandwith? Isn't the data transferred during the GetFieldValue function, so the two queries perform exactly the same?
No, they wont. The data will still be transferred (because that's what you asked the database for) your application will just ignore the rest.
Upcoming events:
* Glasgow: Mock Objects, SQL Server CLR Integration, Reporting Services, db4o, Dependency Injection with Spring ...
"I wouldn't say boo to a goose. I'm not a coward, I just realise that it would be largely pointless."
My website
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Colin's answer is correct. I will also add that if you have an index on columns A and B (or containing columns A and B in the index), SQL Server will consider that a covering index for the query and only scan the index, rather than scanning the table itself.
Because the index occupies less space than the table itself, this will require less I/O and return the results faster.
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Good point - I'd forgotten about that.
Upcoming events:
* Glasgow: Mock Objects, SQL Server CLR Integration, Reporting Services, db4o, Dependency Injection with Spring ...
"I wouldn't say boo to a goose. I'm not a coward, I just realise that it would be largely pointless."
My website
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thats the main point - if columns a and b are indexed you will notice a huge % difference in performance - the number of I/O's will reduce even more.
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blakey404 wrote: thats the main point
It's a point. I don't see how it is the main point. The OP asked about performance for a query. One aspect is indexes, another is returning just the information that is actually needed. Both equally valid, especially as there was no filtering (WHERE clause) involved.
Upcoming events:
* Glasgow: Mock Objects, SQL Server CLR Integration, Reporting Services, db4o, Dependency Injection with Spring ...
"I wouldn't say boo to a goose. I'm not a coward, I just realise that it would be largely pointless."
My website
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i would say its the main point because of how the indexes are stored. if the columns specified to be returned are both in a non-clustered index the data returned can be retrieved directly from that index, therefore not having to do x number of disk reads to return all the columns, as with a select *. try both in query analyzer and see the difference. returning index columns only from a non-clustered index is the fastest query possible, as it reduces logical reads.
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blakey404 wrote: returning index columns only from a non-clustered index is the fastest query possible, as it reduces logical reads.
I don't disagree with that. I'm just saying there are other ways that can help improve performance. Indexing is not the be all and end all of performance improvement.
Upcoming events:
* Glasgow: Mock Objects, SQL Server CLR Integration, Reporting Services, db4o, Dependency Injection with Spring ...
"I wouldn't say boo to a goose. I'm not a coward, I just realise that it would be largely pointless."
My website
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oh i completely agree, i was just thinking about in this particular example - where it is very possible the 2 columns required may be indexed.
 )
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Like Colin said about the network bandwidth, it will take less to only pull the fields that you need at the moment, and it is better for design and maintenance of the code to only pull what you need at that moment in the program. Another thing, do you need to pull the millions of rows at once?
"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon
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No, I don't, as I process the data programmatically from VC++. See my reply to Colin above.
I am not sure the bandwith usage is more for query #2 if queried as above, right?
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Query two shouldn't take up as much bandwidth as query one. The extra bandwidth depends on how many fields are being fetched from the table.
"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon
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hi! i have a table 'Categories' whose schema is:
CategoryId(Primary Key) int
Name nvarchar(25)
i have another table 'Products' whose schema is:
ProductId(Primary Key) int
CategoryId int
Description nvarchar(250)
ProductImage nvarchar(50)
UnitCost money
now i want whenever i delete an category from Categories, then all the data related to this Category from the table Products should be deleted automaticaly from Products table. How is possible?
Thanks & Regards,
SAMir Nigam,
Software Engineer,
STPL, Lucknow, India.
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You have to do cascading deletes. Google Cascading Delete[^] has some good results that can help you out 
"Any sort of work in VB6 is bound to provide several WTF moments." - Christian Graus
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First delete rows in Products table with categoryid whichyou want tobe deleted then delete category from categories table.
example
delete from products where categoryid='1'<br />
delete from categories where categoryid='1'
I Love SQL
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He could always have that in a stored procedure, but cascading delete is easier 
"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon
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I have four tables (t1, t2, t3, t4) in my DB. Given t1 and t4, i want to find what tables(relationship) are between t1 and t4. I want to do this using SQL and/or .NET. Any suggestions?
t1 t2
--------- ---------
t1Id (pkey) t2Id (pkey)
t2Id (fkey) t3Id (fkey)
<br />
t3 t4
--------- ---------
t3Id (pkey) t4Id (pkey)
t4Id (fkey)
The result in this example would be t2, t3
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Start by looking at your primary keys.
"Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon
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Hi all,
I am in a fix for which i really need some input with this problem
colA-------- --COLB
1000-------- --,,,--EXCESS OF ,,,
1000A------- --A,,
100AB------- --A,B,,
100ABC------ --A,B,C,
This result was derived to achive the table Below
DESIRED RESULT
colA-------- --COLB
1000-------- --NULL
1000A------- --A
100AB------- --A
100AB------- --B
100ABC------ --A
100ABC------ --B
100ABC------ --C
BUT THIS IS THE RESULT I GET
colA-------- --COLB
1000-------- --NULL
1000A------- --A
1000A------- --NULL
1000AB------ ---A
1000AB------ ---B
1000AB------ --NULL
100ABC------ --A
100ABC------ --B
100ABC------ --C
THIS IS BECAUSE THE FIRST RESULT CONTAINS ESCESS OS ,,, I WANT TO
REMOVE THOSE AND HAVE ONLY THE VALID LETTERS,
IS THERE A WAY TO REMOVE ONLY THE EXCESS COMMAS
ANY INPUT BE VERY HELPFUL
THANKS
SQL DEVELOPER
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I recommend a regular expression that looks for 1 or more contiguous commas and replaces with a single comma. I can't give you the regex straight away, but maybe you can find one on a regex site somewhere.
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I am using MS Access to make a simple database and i used a lookup field to another table so that the user can update the lookup as needed. But when i copy the records to another table i want them to copy as text data not lookup data. I would like to know how to copy it to another table and get the actual value instead of the foriegn key.
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How can I get more control over generating SQL scripts? I would like to optionally include drops where SSMS only allows drops OR creates etc. I would like to script as alter not create etc.
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