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Thanks Mika!
"I meant a scenario where your try catch is inside a stored procedure and a client application (whatever it is) calls the procedure. Ending point can be at the calling side so the procedure is actually just a part of a bigger transaction scope." -- so in this scenario, client code (e.g. ADO.Net) starts the transaction, but what is the practice of writing store procedure code in this way? Do we also need try-catch and begin transaction/rollback/commit code in store procedure?
BTW: I have this confusion because I as a store procedure developer -- not sure whther client will start another transaction or not. So, how could I write code in store procedure which could handle both client starts transaction or store procedure self-start transaction?
regards,
George
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How the transaction scope is defined is a matter of opinion. I think most people use the logic that stored procedure starts and ends the transaction. However, there are downsides especially if rollback is executed because in that case the whole transaction is rolled back, even if it's started outside the stored procedure.
So this means that you actually cannot decide alone what transaction scope will be used. The application may be affected by your decisions. You could use @@TRANCOUNT to investigate if transaction is started outside the procedure and in the logic of your stored procedure you would execute rollback based on the initial transaction count.
There's a very good article you should read: http://www.codeproject.com/KB/database/sqlservertransactions.aspx[^]
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George_George wrote: 1. For single SQL insert/update/delete statement, are there any needs or benefits to wrap into a transaction?
No, there are no benefits in this case.
George_George wrote: Any means to commit transaction automatically
This tells you all about it MSDN[^]
Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP
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Thanks Ashfield!
Two more comments/questions after learning,
1.
I want to confirm with you that if we call begin transaction, do you mean the only way to commit transaction is to explicit call commit?
2.
If I do not use begin transaction explicitly using begin transaction statement (the default behavior is to auto-commit for each successful statement), no other configurations to disable auto-commit for successful each statement -- means we could have chance to commit later in a batch manually explicitly?
regards,
George
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George_George wrote: I want to confirm with you that if we call begin transaction, do you mean the only way to commit transaction is to explicit call commit?
Correct
George_George wrote: means we could have chance to commit later in a batch manually explicitly?
No - the default autocommit will have happened
Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP
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Thanks Bob,
Sorry one more question, there are 3 modes, autocommit, explicit and implicit. How to disable/enable implicit mode? 
regards,
George
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I don't think you can, but you will need to check the documentation
Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP
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I am using the following code to Add up the difference of two time fields but It's not showing the correct record when the hours part increases above 24 means It shows the correct addition only if It's between 24 hours. For example
WaitingTimeTotal (hh:mm:ss)
----------------
03:18:46
03:25:06
________
06:43:52 which is correct but
WaitingTimeTotal (hh:mm:ss)
----------------
03:18:46
03:25:06
16:23:46
07:24:20
________
wrong answer!!!
The code i am using is
convert(varchar,convert(DateTime, SUM(convert(real, ConfTime - EnterTime))),108)WaitingTimeTotal
Can you please guide me. Thanks in advance !
AliAmjad(MCP)
First make it Run THEN make it Run Fast!
modified on Thursday, January 15, 2009 1:28 AM
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If you want to have total hour amount, this could be one way.
I used inline views to both generate a test data (inner one) and to ease the summary (the outer one).
select convert(varchar(50), datepart(hour, datesum) + (datepart(day, datesum) - 1) * 24)
+ ':' + convert(varchar(50), datepart(minute, datesum))
+ ':' + convert(varchar(50), datepart(second, datesum))
from (select SUM(convert(real, datecolumn)) as datesum
from (select CONVERT(datetime, '03:18:46') as datecolumn
union
select CONVERT(datetime, '03:25:06') as datecolumn
union
select CONVERT(datetime, '16:23:46') as datecolumn
union
select CONVERT(datetime, '07:24:20') as datecolumn) alias1
) alias2
Now the result is 30:31:57. Was this what you were after?
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Hi, i just attended an interview and was asked about the difference between MS SQL and ORACLE ? plz help by providing the striking features between these.
Thanx,Subin
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Well, if you have to ask this then you obviously have not grasped one of the important concepts of being a developer - DO YOUR OWN RESEARCH! Google gave about 1.5 million hits for "compare oracle sql server"
Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP
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Comparing two different products this way is IMO impossible. Instead of comparing blindly features or capabilites or products in the overall product suites, you should concentrate on the requirements. If you can define what you or the customer needs, then there would be a starting point to conversation considering if one product can fulfill a requirement better than another.
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Don't expect a call-back.
"Well, we're getting "F"'d at work. WPF, WCF, and WWF... WTF?" --John Simmons
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Hi all
I have tried to do one general procedure for insert,update,delete.
first i am trying insert.I have one problem:how to pass dynamic parameters and values in stored procedure?
Thanks
monika
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Could you specify a little more, what do you mean by dynamic parameters. The amount of parameters or the amount of data passed using a parameter, dynamic datatype etc.
If it's possible to describe the scenario it would help.
Mika
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If your intention is to create dynamic SQL strings in a general procedure and execute them, I would not recommend it. First, creating dynamic strings in a .NET enviornment is a bad thing unless you use the stringbuilder class. Second, by creating strings and having the SQL engine execute them will force the SQL engine to parse and develop an execution plan for each statement, this could lead to high CPU usage on your DB server depending on how many SQL statements are being processed per second. You should try to use parameterized queries or stored procedures when dealing with a DB engine, then each time a similar query is requested the statement is already parsed and an execution plan has already been choosen, it will just substitue the parameters in and return your rows. In general, dynamic SQL bad. This is true for almost all DB engines not just MS-SQL server.
Just something to think about ...
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If you're using sql2k8 you can use Table Value Parameters.
If you're using sql2k5 you can simulate this by passing a list to a stored procedure using XML parameters.
Ryan
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monika_vasvani wrote: I have tried to do one general procedure for insert,update,delete.
Bad practice. The first time the stored proc runs it gets optimised - say it happens to be an insert. The next time it runs it will use the same query plan (as it will be cached), but you may be doing an update, so the optimal query plan would be totally different. This can lead to performance issues. If you want a single proc to call for all the actions have one, but have it call a different proc for insert, another proc for update eetc.
Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP
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Hello everyone,
I create the following table,
create table ABC (a varchar unique);
then create the following store procedure,
CREATE PROCEDURE [dbo].[prc_AddABC]
AS
BEGIN
INSERT INTO [dbo].[ABC]
values ('a');
SELECT @@ERROR AS ABCERROR;
END -- end of store procedure
After execute the procedure twice, which will cause insert duplicate value 'a' on unique column a error.
What I got from Management Studio is,
ABCERROR 2627
return value -4
My question is, why @@error is not the same as return value? what does the message and return value mean? Where could I find
related documents to read their meanings?
thanks in advance,
George
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@@error gives you the error number as SQL Server generates it. You can use it to identify the problem that occured in the database. Described: http://msdn.microsoft.com/en-us/library/ms188790(SQL.90).aspx[^]
George_George wrote: return value -4
Depends where you got this from. If you got this in an exception at client side, it most likely describes the error that the library sees (OleDbCommand, SqlCommand etc.) If thats the case, you can find the SQL Server error number inside the exception.
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Thanks Mika,
I got this error from Management Studio when execute the store procedure I posted in my post. My confusion is, @@ERROR is enough for us to track the exact error, why there is an addtional return value? And who returns -4 -- I did not write return -4 in my store procedure code posted.
regards,
George
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George_George wrote: @@ERROR is enough for us to track the exact error
That's true.
George_George wrote: who returns -4 --
This is something I don't understand. If I create your procedure, run it twice, I get the following result:
Msg 2627, Level 14, State 1, Procedure prc_AddABC, Line 3
Violation of UNIQUE KEY constraint 'UQ__ABC__3BD0198F4316F928'.
Cannot insert duplicate key in object 'dbo.ABC'.
The statement has been terminated.
(1 row(s) affected)
And that's expected. However, no -4 anywhere. Can you post the whole result of your test.
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Hi Mika!
-4 is found from the results window and what you posted is found from message window. I have a screen snapshots, but how could I post here?
BTW: in the message window, I got the same result. But my confusion is the information in the results window -- there are two tabs, one for results window and one for message window.
Could you see the same content in result window?
regards,
George
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Yes that info was from messages window. My result window has this (on the grid, right click / select all / copy with headers):
ABCERROR
2627
So it prints out @@ERROR which is exactly what your procedure does. No -4.
Are you sure the procedure is like in your post? No modifications done? Use the scripting ability and script it to for example query window to see if you do something after the SELECT @@ERROR AS ABCERROR;
About the question of scripting several procedures at the same tame, use the wizard for the database. Select db, right click then Tasks / Generate Scripts... From there on it's simple. Select what you want.
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