I am running a Select query and getting lots of rows from it(sometimes more than 500) then inserting thoes values one by one into another table. Now i want to know which insert step failed so that i can start inserting from that failed step again so that table does not update with duplicate value.
Syntax may vary from system to system, however structure and process remains.
When one does database deployments to live system he prepares two SQL scripts.
1.Change script that has structure like this:
PRINT 'Doing X'
SCRIPT X
....
GO
PRINT 'DOING Y'
SCRIPT Y
....
GO
2.Rollback script that reverts all the changes that section of script does.
Revert scripts are executed in reverse order.
REVERT SCRIPT Y
REVERT SCRIPT X
When change script fails you will know which section failed by the last message printed out, then you will take all sections of rollback script that run after the failed section and revert changes.
Related
Consider the following bit of SQL
SET DATEFORMAT ymd
SET ARITHABORT, ANSI_PADDING, ANSI_WARNINGS, CONCAT_NULL_YIELDS_NULL, QUOTED_IDENTIFIER, ANSI_NULLS, NOCOUNT ON
SET NUMERIC_ROUNDABORT, IMPLICIT_TRANSACTIONS, XACT_ABORT OFF
GO
USE master
GO
IF DB_NAME() <> N'master' SET NOEXEC ON
--
-- Create database [myDatabaseName]
--
PRINT (N'Create database [myDatabaseName]')
GO
CREATE DATABASE myDatabaseName
There is then a very long script setting up tables, views, stored procedures etc etc.
I would like to know if SQL would allow something along the likes of the following pseudo code;
If (myDatabaseName Exists)
Return // in other word abort the script here but don't throw an error
Else
//Carry on and install the database
I am aware of the Exists function in SQL but I can't seem to find anything that would simply abort the remains of the script straightaway.
This script will end up in an installation routine. In theory it should never be in an installer where the database is already present, however I would prefer not to take chances and prepare properly for a potential mistake. It is also crucial that the script does not throw any error as that will just cause the installer to roll back and install nothing.
I'm hoping that something exists in SQL that will just exit a script cleanly if particular conditions are met. By exit I really do mean exit as opposed to simply breaking out of the condition being currently evaluated.
The problem is, your client tool (SSMS, SQLCMd, etc) splits your script into batches based on the location of the GO keyword (it's a client tool thing, not SQL Server at all).
It then sends the first batch. After the first batch is complete (no matter what the outcome), it sends the second batch, then the third after the second, etc.
If you're running with sufficient permissions, a high-valued RAISERROR (severity 20-25) should stop the client tool in its tracks (because it forces the connection closed). It's not that clean though.
Another option is to try to set NOEXEC ON which still does some work with each subsequent batch (compilation) but won't run any of the code1. This allows you a slightly better recovery option if you want some batches at the end to always run, by turning it OFF again.
1Which means you still will see error messages for compilation errors for later batches which rely upon database structures that would have been created in earlier batches, if they weren't being skipped.
You can use GOTO as follows :
If (myDatabaseName Exists)
GOTO QUIT; // in other word abort the script here but don't throw an error
Else
//Carry on and install the database
QUIT:
SELECT 0;
There are several methods for that kind of request :
raiserror('Oh no a fatal error', 20, -1) with log
OR
print 'Fatal error, script will not continue!'
set noexec on
They should work and close the connection.
See here : Answer
I have a stored procedure that I execute through SSIS using an execute sql task. It appears to work on SISS, but when I look at the database the record is not created. The connection is for the correct database. The PROBLEM.
I have put a breakpoint ON and checked all the variables getting fed IN AND THEN ran it manually IN SQL SERVER management.
The SP work perfectly in SSMS with the same input parameters, but when executed through SSIS, it does not create the records required and does not give any error out.
In the SP I have a try catch to put any erorrs in the stored procedure when it erorr out to a table, but there is no entry for the SSIS run. According to the Error table for the SP and SSIS it looks like it executed successfully. When I go to see if the record it is not created. I cannot see the problem. Is there something I can put into the stored procedure to debug this problem or anything further I can do in SSIS to work this out ?
It has been 3 hours on this problem so looking for a fresh perspective to work out what is happening.
The SSIS package definitely points to the correct database and stored procedure.
From the watch window it appears to be giving all the parameters the correct values and does not error in SSIS.
Worked it out with sql profiler . In the Target database there is sequence that is incremented each time a new record needs to be created . When I deleted the record to rerun it it created it with a different ID number , I was expecting it to be created with the same ID number.
Thanks Billinkc !
We have an SSIS package that ran in production on a SQL 2008 box with a 2005 compatibility setting. The package contains a SQL Task and it appears as though the SQL at the end of the script did not run.
The person who worked on that package noted before leaving the company that the package needed "GOs" between the individual SQL commands to correct the issue. however, when testing in development on SQL Server 2008 with 2008 compatibility, the package worked fine.
From what I know, GO's place commands in batches, where commands are sent to the database provider in a batch, for efficiency's sake. I am thinking that the only way that GO should effect the outcome is if there was an error in that script somewhere above it. I can imagine GO in that case, and only that case, effecting the outcome. However, we have seen no evidence of any errors logged.
Can someone suggest to me whether or not GO is even likely related to the problem? Assuming no error was encountered, my understanding of the "GO" command suggests that it use or lack of use is most likely unrelated to the problem.
The GO keyword is, as you say, a batch separator that is used by the SQL Server management tools. It's important to note, though, that the keyword itself is parsed by the client, not the server.
Depending on the version of SQL Server in question, some things do need to be placed into distinct batches, such as creating and using a database. There are also some operations that must take place at the beginning of a batch (like the use statement), so using these keywords means that you'll have to break the script up into batches.
A couple of things to keep in mind about breaking a script up into multiple batches:
When an error is encountered within a batch, execution of that batch stops. However, if your script has multiple batches, an error in one batch will only stop that batch from executing; subsequent batches will still execute
Variables declared within a batch are available to that batch only; they cannot be used in other batches
If the script is performing nothing but CRUD operations, then there's no need to break it up into multiple batches unless any of the above behavioral differences is desired.
All of your assumptions are correct.
One thing that I've experienced is that if you have a batch of statements that is a pre-requisite for another batch, you may need to separate them with a GO. One example may be if you add a column to a table and then update that column (I think...). But if it's just a series of DML queries, then the absence or presence of GO shouldn't matter.
I've noticed that if you set up any variables in the script their state (and maybe the variables themselves) are wiped after a 'GO' statement so they can't be reused. This was certainly the case on SQL Server 2000 and I presume it will be the case on 2005 and 2008 as well.
Yes, GO can affect outcome.
GO between statements will allow execution to continue if there is an error in between. For example, compare the output of these two scripts:
SELECT * FROM table_does_not_exist;
SELECT * FROM sys.objects;
...
SELECT * FROM table_does_not_exist;
GO
SELECT * FROM sys.objects;
As others identified, you may need to issue GO if you need changes applied before you work on them (e.g. a new column) but you can't persist local or table variables across GO...
Finally, note that GO is not a T-SQL keyword, it is a batch separator. This is why you can't put GO in the middle of a stored procedure, for example ... SQL Server itself has no idea what GO means.
EDIT however one answer stated that transactions cannot span batches, which I disagree with:
CREATE TABLE #foo(id INT);
GO
BEGIN TRANSACTION;
GO
INSERT #foo(id) SELECT 1;
GO
SELECT ##TRANCOUNT; -- 1
GO
COMMIT TRANSACTION;
GO
DROP TABLE #foo;
GO
SELECT ##TRANCOUNT; -- 0
what is the best way of troubleshoot a stored procedure in SQL Server, i mean from where do you start etc..?
Test each SELECT statements (if any) outside of your stored procedure to see whether it returns the expected results;
Make INSERT and UPDATE statements as simple as possible;
Try to test Inserts and Updates outside of your SP so that you can check it gives the expected results;
Use the debugger provided with SSMS Express 2008.
Visual Studio 2008 / 2010 has a debug facility. Simply connect to to your SQL Server instance in 'Server Explorer' and browse to your stored procedure.
Visual Studio 'Test Edition' also can generate Unit Tests around your stored procedures.
Troubleshooting a complex stored proc is far more than just determining if you can get it to run or not and finding the step which won't run. What is most critical is whether it actually returns the corect results or performs the correct actions.
There are two kinds of stored procs that need extensive abilites to troublshoot. First the the proc which creates dynamic SQL. I never create one of these without an input parameter of #debug. When this parameter is set, I have the proc print the SQl statment as it would have run and not run it. Almost everytime, this leads you right away to the problem as you can then see the syntax error in the generated SQL code. You also can run this sql code to see if it is returning the records you expect.
Now with complex procs that have many steps that affect data, I always use an #test input parameter. There are two things I do with the #test parameter, first I make it rollback the actions so that a mistake in development won't mess up the data. Second, I have it display the data before it rollsback to see what the results would have been. (These actually appear in the reverse order in the proc; I just think of them in this order.)
Now I can see what would have gone into the table or been deleted from the tables without affecting the data permananently. Sometimes, I might start with a select of the data as it was before any actions and then compare it to a select run afterwards.
Finally, I often want to log actions of a complex proc and see exactly what steps happened. I don't want those logs to get rolled back if the proc hits an error, so I set up a table variable for the logging information I want at the start of the proc. After each step (or after an error depending on what I want to log), I insert to this table variable. After the rollback or commit statement, I select the results of the table variable or use those results to log to a permanent logging table. This can be especially nice if you are using dynamic SQL because you can log the SQL that was run and then when something strange fails on prod, you have a record of which statement was run when it failed. You do this in a table variable because those do not go out of scope in a rollback.
In SSMS, you can simply start by opening the proc., and clicking on the check mark button (Parse) next to the Execute button on the menu bar. It reports any errors it finds.
If there are no errors there and you're stored procedure is harmless to run (you're not inserting into tables, just creating a temp table for example), then comment out the CREATE PROCEDURE x (or ALTER PROCEDURE x) and declare all the parameters by copying that part, then define them with valid values. Then run it to see what happens.
Maybe this is simple, but it's a place to start.
I have a TSQL script that is used to set up a database as part of my product's installation. It takes a number of steps which all together take five minutes or so. Sometimes this script fails on the last step because the user running the script does not have sufficient rights to the database. In this case I would like the script to fail strait away. To do this I want the script to test what rights it has up front. Can anyone point me at a general purpose way of testing if the script is running with a particular security permission?
Edit: In the particular case I am looking at it is trying to do a backup, but I have had other things go wrong and was hoping for a general purpose solution.
select * from fn_my_permissions(NULL, 'SERVER')
This gives you a list of permissions the current session has on the server
select * from fn_my_permissions(NULL, 'DATABASE')
This gives you a list of permissions for the current session on the current database.
See here for more information.
I assume it is failing on an update or insert after a long series of selects.
Just try a simple update or insert inside a transaction. Hard-code the row id, or whatever to make it simple and fast.
Don't commit the transaction--instead roll it back.
If you don't have rights to do the insert or update, this should fail. If you DO, it will roll back and not cause a permanent change.
try the last insert/update up front with some where condition like
insert/update
where 1=2
if (##error <> 0)
raise error 6666 'no permissions'
this would not cause any harm but would raise a flag upfront about the lack of rights.