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I´ve used the DataReader, DataSet, ExecuteScalar, etc. However Im not sure what of these is the best solution for the following problem:
I want to use a simple SELECT and loop through the data, and update some of the data but make sure no two persons can UPDATE some of the selected transactions at the same time.
I could loop through the data with ExecuteScalar or DataReader, but would it allow two users to update the same data at the same time? (without locking the database)
Thanks in advance 
BinaryHead
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BinaryHead wrote:
make sure no two persons can UPDATE some of the selected transactions at the same time.
transactions? You mean rows, surely.
Personally I'd create a stored procedure for this sort of thing (if possible) which has the added advantage of a single round trip to the database.
Anyway, you can create a transaction and run multiple commands in the same transaction and then commit it. There is an example here on MSDN[^]
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There are many different ways of ensuring that the rows are not modified while you are accessing them. But, let me ask you first - is it feasable that the data in the db can be altered by means other than your application?
Ensuring optimitic locking inside your application only works if everyone is using your application to access the data. If others might have access to the data outside of your application, you'll most likely want to push all your updates into a transaction and set the isolation level accordingingly.
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There could be many people accessing the same data at the same time using this application (many instances/copies of my program) Im trying to build (but not accessing the data with some third party application).
Im just scared of one thing:
- If two different programs, A and B, are running at the same time(both using the same database) and A requests some rows with the DataReader (f.ex. SELECT... where some Boolean == false) and at the same time B updates some of the SAME rows (UPDATE...where ..SET Boolean == true).
Is the DataREader in A smart enough to SELECT some rows, and then while looping through them, figure out that one of the rows has been changed (Boolean == true) so it should skip it in the loop? (or are the rows that the DataReader returns just copied into memory and then looped blindly like the DataSet with Adapter.Fill() / Adapter.Update()? ).
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Hey there
Im busy trying to set up transactional replication between a server in one city and a backup server in another. When i try Configure the publisher/distributor I get to the end of the wizard and while trying to configure the distributor it gives me an error:
Error 18483: couldnt connect to server x because 'distributor_admin' is not defined as a remote login at the server
Im pretty new to this whole replication thing
Any advice?
I would really appreciate it.
Nick
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I have a simple CE.NET application running on a embedded machine running Windows CE.NET 4.2 and SQL Server 2000 CE Edition 2.0. In this application I am using a standard SqlCeCommand object to run the following query:
<br />
UPDATE tblschedules<br />
SET tblschedules.result =<br />
(<br />
CASE WHEN EXISTS<br />
(<br />
SELECT * FROM tblscheduledetails<br />
WHERE tblscheduledetails.schedule = tblschedules.id AND<br />
tblscheduledetails.result = 1<br />
)<br />
THEN 1<br />
ELSE 0<br />
END<br />
)
The query results in a "A native exception occured" just as soon as I do a ExecuteNonQuery() on the object. The query itself runs without problems when running it from the CE Query Analizer. Does anybody have an idea what might be the problem?
We are the all singing, all dancing crap of the world. - Tyler Durden
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Hi.
I set an INSTED OF INSERT trigger on a table, that deny the addition of rows in some conditions.
My question is:
When I run the insert command, I get the (X row(s) affected) message, even if that isn't the real number of added rows.
I tried to set the @@ROWCOUNT function, but it turns out this isn't the way.
Is there any way to change the affected rows count of a trigger / sp?
Thanks,
Yaakov
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I went to a TechNet presentation about SQL Server 2005 and for some reason fell in love with the circular "busy" animation it plays(which, when completed, changes to a big checkmark in a circle). I was wondering if anyone knew if these where public images and are going to be included in the VS.Net 2005(I know they are including a file of icons and animations that are used in VS.Net, but not sure if from any of their other products).
Or if anyone knew a PD file out there that looks simular.
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Hi All,
I would like to know;How Connection pooling will impact on security?
Thanks in Advance.![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif)
anju
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anju wrote:
How Connection pooling will impact on security?
To my knowledge it doesn't.
Connection pooling is just a way that a .NET application re-uses the same connection to the database in different parts of an application. The connection must be the same as an existing connection in the pool, if not then a new connection is created.
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Thank you for your quick reply.
What I am looking is ....
To implement connection pooling the connection strings must be identical.(am I right?).If this is the case,for different UserIds and Passwords the connection string is always different,then how connection pooling will be helpful?.
anju
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anju wrote:
To implement connection pooling the connection strings must be identical.(am I right?).
Yes. That is correct.
anju wrote:
If this is the case,for different UserIds and Passwords the connection string is always different,then how connection pooling will be helpful?.
Because you create a connection, use the connection and then close the connection. Next time you access the database you repeat the create, use, close routine again. The second time round the connection will be in the pool and you get it quickly.
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If we want performance and scalability,Do we need to compramise about security?
anju
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Then, Could you pleae explain me the way to Manage Security with Connection Pooling.
anju
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As I have said already: Connection pooling is just a way that a .NET application re-uses the same connection to the database in different parts of an application. The connection must be the same as an existing connection in the pool, if not then a new connection is created.
It is NOT a way to manage security. It is a way to repeatedly use the same connection to the database.
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Thank you for your explanation.
anju
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anju wrote:
for different UserIds and Passwords the connection string is always different
Yes it is, but, then you don't use different user IDs/passwords in your application. If your application needs logins, you create a table in your database with the user name and passwords *for your application*.
Then you create one single SQL Server user that only has access to run stored procedures on your application's database. This is the user ID you use everywhere in your application to access your database (of course, you must have stored procedures to access all tables.)
When a user logs in your application, you find out in your database using the stored procedures what permissions that user has, and selectively enable/disable parts of your application.
But you only should have one database user ID/password, and use that in your connection string (never sa). This way, all the connection strings will be the same, and connection pooling will work fine.
-- LuisR
Luis Alonso Ramos
Intelectix - Chihuahua, Mexico
Not much here: My CP Blog!
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I'd agree with that in general, but there are times that it's not practical, for example if you have a service that's running as SYSTEM with the database on another machine. Yes, I know that it's bad practice to have a service running as SYSTEM unless absolutely necessary - unfortunately this is a legacy service with UI and therefore has to run as an interactive service, hence it has to run as SYSTEM.
It's useful to note that you don't need a domain to set this up, but if you don't have one, you'll need to create user accounts for the appropriate users on the server hosting SQL Server, and add them to SQL Server's logins. You then need to synchronize the passwords for those user accounts between the machine that the client runs on and the server hosting SQL.
One thing you can do with Windows Authentication that you can't with SQL Server Authentication is to set up groups of users with particular permissions.
Stability. What an interesting concept. -- Chris Maunder
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Colin Angus Mackay wrote:
Actually, I'd use windows authentication
Well, yes. But if he were using Windows Authentication, then he wouldn't be having problems with different connection strings: it would always be the same. But still, Mike's reply shows some situations where it isn't practical. In my current application, there's Windows Server with a MSDE and several other machines accessing it. The network is not configured with a domain, so its easier to just use sa with a blank password.
Just kidding, I have a SQL server user with limited permissions and I use SQL login info and store the connection string encrypted. 
-- LuisR
Luis Alonso Ramos
Intelectix - Chihuahua, Mexico
Not much here: My CP Blog!
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I want to zip files using a freely available Zip component which is available for download from the below address
http://www.xstandard.com/page.asp?p=C9891D8A-5390-44ED-BC60-2267ED6763A7&ss=D6DD5252-781D-47AE-900A-29F56BB7DFFE
The Following is the way i'm trying to zip the file but i m not able to Zip the file and save it
Please help me.
DECLARE @Result int, @Zipper int, @FileID int ,@source varchar(255), @description varchar(255)
execute sp_OACreate 'XStandard.Zip', @Zipper OUT
execute @Result = sp_OAMethod @Zipper, 'Pack', @FileID,'c:\\helloSQL.txt','c:\\wilbur.zip',true,9
Regards
Wilbur J. Pereira
"If they love me let them, for the heck of it.If they don't, who da heck cares about it"
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I am creating a ASP.NET web application that allows users to execute DTS packages stored on the server. IIS has integrated windows authentication enabled. When the user executes the DTS package, I need the package to use the user's windows account to connect to the database. I have enabled integrated security, and according to the log file created when the DTS package is executed, my windows username is captured as the user who executes the package, but the database connections are made with the ASPNET account. How would I get the DTS package to use windows authentication? 
Thanks.
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