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Yikes - wish I hadn't asked.
Okay, well, I'd be looking for the first reported error and concentrate on that:
Starting up database 'master'.<br />
Error: 17207, Severity: 16, State: 1.
Start with that and see how far you get. (If anyone else has a better suggestion now would be the time...)
me, me, me
"The dinosaurs became extinct because they didn't have a space program. And if we become extinct because we don't have a space program, it'll serve us right!"
Larry Niven
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Hello,
let's have the following simple example. An SQL table consists of three columns:
RecordId,
GenerationId,
Fitness.
RecordId is a unique key. GenerationId and Fitness columns contain values that might and do repeat themselves over many rows.
Now how to do a simple select of the unique RecordId which has the highest Fitness, grouped by GenerationId?
Obviously,
SELECT max(Fitness) FROM myTable GROUP BY GenerationId
returns the highest Fitness for each GenerationId, but how to get the particular row which has this highest Fitness?
Fitness values might repeat themselves for the same GenerationId values, so an aggregate function also has to be used to select a distinct RecordId for a particular GenerationId. It doesn't matter which RecordId is selected as long as it has the highest Fitness for the particular GenerationId.
Thank you very much for any ideas!
Michal
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the result should look something like this:
GenerationId, Fitness, RecordId
0,312.53,12
1,365.42,18
2,412.56,28
3,418.26,34
4,526.79,41
5,528.,48
...
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Do you have some sample data for the table that would be used to get the result you're looking for?
Scott
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yes, let's use the following sample data.
source table:
RecordId GenerationId Fitness
0 0 150.5
1 0 148.2
2 0 172.5
3 1 183.2
4 1 189.8
5 1 183.2
6 1 215.1
7 1 221.3
8 2 208.4
9 2 232.1
10 3 225.1
11 3 236.4
12 3 231.5
13 3 236.4
14 4 236.4
15 4 245.1
16 5 251.9
17 5 250.4
18 6 251.9
19 6 262.4
based on how one aggregates multiple rows with the same Fitness for the same GenerationId, one of the possible outcomes should look like the following. here I used max(RecordId), but it doesn't really matter:
GenerationId maxFitness RecordId
0 172.5 2
1 221.3 7
2 232.1 9
3 236.4 13
4 245.1 15
5 251.9 16
6 262.4 19
I'm able to achieve this result with joining the source table to itself, but I hope there has to be a more elegant way on how to do this without breaking one's neck with multiple lines of SQL code.
thanks for any help and ideas!
Michal
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SELECT g.GenerationId,
d.Fitness,
d.RecordId
FROM
(
SELECT DISTINCT GenerationId
FROM [Source]
) AS g
CROSS APPLY
(
SELECT TOP 1 s.RecordId, s.Fitness
FROM [Source] AS s
WHERE s.GenerationId = g.GenerationId
ORDER BY s.Fitness DESC
) AS d
ORDER BY g.GenerationId ASC
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Personally, I don't see a problem with joining to the source table itself, or an inline view built off of the source table, so I came up with this which returns your desired result:
SELECT cp.generationid, cp.fitness, MAX(cp.recordid)
FROM cp,
(SELECT generationid, MAX(fitness) maxfitness
FROM cp
GROUP BY generationid) view1
WHERE cp.fitness = view1.maxfitness AND cp.generationid = view1.generationid
GROUP BY cp.generationid, cp.fitness
ORDER BY 1, 2, 3
view1 is an inline view off of the original table that I'm joining to.
I saw i.j.russell's response, but I'm not familiar with it (I'll need to read up on it).
Scott
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Thank you very much for all your replies!
I used my original code with joining the table to itself at last. I was looking for some really simple way on how to handle this, but it looks there's no free lunch in T-SQL 
Thanks again for all your valuable input!
Michal
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Let's assume I have such table:
Pictures:
p_id
p_name
p_path
p_userId_mobile_addition [int]
p_userId_mobile_modification [int]
p_userId_www_addition [uniqueidentifier]
p_userId_www_modification [uniqueidentifier]
p_userId_mobile keys reference UsersMobile table.
p_userId_www keys reference UsersWWW table.
These keys give us information about the user that added or modified the picture. There are 4 keys as addition and modification can be performed with www or PocketPC interface.
How to create a view presenting:
1. p_id,
2. p_name,
3. p_path
4. username (from UsersMobile or UsersWWW) for addition
5. username for modification through www
6. username for modification through PocketPc
Platform: MS SQL Server 2005
Best regards,
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where is the problem? 
what did you try?
we make no query for you 
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Try something similar to this:
select p_id,
p_name,
p_path,
case when uw.username is not null then uw.username
when um.username is not null then um.username
else null
end creator,
uw.username,
um.username
from pics
left join usersmobile um
on pics.p_userId_mobile = um.p_userId_mobile
left join UsersWWW uw
on pics.p_userId_www = uw.p_userId_www
But your problem is really bigger than the query, your datamodel isn't very good.
You need to normalize the tables to avoid corruption of your data
Here's a suggestion (with room for improvement):
Image
imageid PK
name
path
users
userid PK
username
accesstype
accesstypeid PK
accesstype
useraccess
useraccessid PK
userid FK
accesstypeid FK
unique key (userid,accesstypeid)
imagecreated
imagecreatedid PK
imageid FK
useraccessid FK
createdate
unique key (imageid,useraccessid)
imagechanged
imagechangedid PK
imageid FK
useraccessid FK
changedate
As this allows storage of several changes per image you need to rethink your original query, or use max(changedate) to get the last change
"When did ignorance become a point of view" - Dilbert
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Dear All,
My question is: where the actual files stored in the database, i.e: if i have records of pdf files, are these files saved in the database tables of application it self (oracle, sql2008), or it will be some where on the H.D. and the path will be recorded in the database tables, lets say Oracle D.B??
Any clarification guys,
Thanks in advance.
0 will always beats the 1.
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Depends on the datatype. If it's a BLOB the file is stored directly in the database. If it's BFILE a reference to the filesystem is stored in the table.
This answer is valid for Oracle. I would be surprised if SqlServer didn't have the same possibilities.
"When did ignorance become a point of view" - Dilbert
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Thanks Jörgen
0 will always beats the 1.
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You're welcome.
"When did ignorance become a point of view" - Dilbert
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Hy, im evaluating how to implement Audit trail in a multi-tier .NET 3.5 Database driven Webapplication based on nettiers and SQL-Server 2008.
I read a lot about the subject, but im still not sure whats the easiest way to do it.
Is it possible at all to implement it (without refactoring everything) with the entity framework if the rest of the application never used the EF?
Or do you guys think, that triggers would do the job just fine?
Ah, and a 2nd question: Do I get this right, that frameworks like log4net are just for logging debug-infos and not for audittrail?
thanx a lot for any input!
Andreas
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andreas.schaerer wrote: that triggers would do the job just fine
Sorry, stopped reading at this point. Anyone who has positive thoughts about triggers needs to be taken out and boiled in oil, shot, drawn and quartered and then made to support the abomination they have created. I hate triggers.
I know they are the "recommended" solution to this problem but I still hate em. I have also never had to implement a really stringent auditing solution. You also need to define the level of auditing you need to do. We usually settle for a log of who changed the record and when, tracking from and to data is whole nother level of nasties.
Never underestimate the power of human stupidity
RAH
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I worked on a system that had some quite strict auditing requirements and the way we managed it was to lock down the tables in the database so that only DBAs had direct update access to the tables. Any updates to the tables by anyone else had to be via stored procedures. Built in to every stored proc was a bit of code that wrote out the audit history of what was happening (which table, which columns, old data, new data, date and time, user id, etc.).
But it sounds as if you want to keep the impact on your existing system to a minimum, in which case you may end up having to use triggers as the least painful option.
As for log4net, it is a generic logging system that can log pretty much anything you want it to log about the behaviour of your system. You can use it to log debug info, you can also use it to log error conditions for later investigation, you can also use it to log configuration information at system start up, anything you want. I suppose you could use it as part of an audit system in your application, depending on what your requirements were and how strict it needed to be.
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we can get an encrypted text by using the below keyword
DBMS_UTILITY.GET_HASH_VALUE in oracle
I need to decript the particular string passed to this keyword
for Eg:
SELECT LTRIM (TO_CHAR ( DBMS_UTILITY.GET_HASH_VALUE ( 'ADMINISTRATOR',2,1048576))) FROM dual;
this will return the encrypted text of 'ADMINISTRATOR' as 121216
But to get the Decryption of that 121216 as 'ADMINISTRATOR'.. is there any keyword used in oracle??
Please help me out..
Thanks in advance..
Stanly.S
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Hashing is not encryption, hashing is a reduction in size, somewhat like an executive summary; it implies throwing away information, hence a one-way operation.
A common practice is to hash passwords and store the result, not the password itself. To check an incoming password, calculate its hash, and compare against the expected hash. No way to retrieve the password, it isn't there at all.
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Hi guys
I have two fields, FirstName and LastName. I am able to concatnate both names but if one of the name is null then I don't get the results. For example, First name is John and there is no last name then upon concatanting both names i get null.
I have set the database "Concatenate Null yeilds Null" to True but still no success. Perhaps, could anyone of you help me.
Thanks
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netJP12L wrote: First name is John and there is no last name then upon concatanting both names i get null.
netJP12L wrote: I have set the database "Concatenate Null yeilds Null" to True
It sounds like this is doing exactly what you told it to. You could:
1) follow i.j.russell's suggestion and use COALESCE, [edit - added]
2) try changing the setting,
3) write code that tests for Null and handles the various cases, or
4) don't allow Null values in these fields.
Looking through the list, i.j.russell's suggestion sounds very good to me.
Please do not read this signature.
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