CREATE TRIGGER [Ins] ON [databasename].[dbo].[tablename]
AFTER INSERT
AS
BEGIN
DECLARE #timerange as INT
SET #timerange = 40
UPDATE [databasename].[dbo].[tablename]
SET [column2] = (SELECT TOP 1 [column1]
FROM [CIMPLICITY].[dbo].[tablename] AS s2
WHERE DATEDIFF(MI,s2.[timestamp],[databasename].[dbo].[tablename].[timestamp]) <= ROUND([databasename].[dbo].[tablename].[column3],0))
WHERE
DATEDIFF(MI,[timestamp], SYSDATETIME()) < #timerange
END
GO
After adding a new row to the table, the trigger must recalculate the value in column 2.
The value in column 2 = the value in column 1 at offset backwards by minute equal to the value in column 3.
Trigger works, but the application that fill the table with data, stops working after the trigger.
I think that the error in the trigger code.
In advance I thank and sorry for my googletranslate english :)
Maybe your problem is that the trigger updates every record in the table, rather than just the inserted record(s).
If so, add another WHERE condition:
WHERE [primary key column] IN
(SELECT [primary key column] from inserted)
inserted is the alias for all records handled by the current INSERT statement.
Probably trigger recursion. Check the TRIGGER_NESTLEVEL and return if value is larger than one:
http://technet.microsoft.com/en-us/library/ms182737%28v=sql.90%29.aspx
I'm find a solution to the problem: it was necessary to add SET NOCOUNT ON after BEGIN.
I do not know why, but it working :)
Related
I have a trigger on a table for insert, delete, update that on the first line gets the current date with GetDate() method.
The trigger will compare the deleted and inserted table to determine what field has been changed and stores in another table the id, datetime and the field changed. This combination must be unique
A stored procedure does an insert and an update sequentially on the table. Sometimes I get a violation of primary key and I suspect that the GetDate() returns the same value.
How can I make the GetDate() return different values in the trigger.
EDIT
Here is the code of the trigger
CREATE TRIGGER dbo.TR
ON table
FOR DELETE, INSERT, UPDATE
AS
BEGIN
SET NoCount ON
DECLARE #dt Datetime
SELECT #dt = GetDate()
insert tableLog (id, date, field, old, new)
select I.id, #dt, 'field', D.field, I.field
from INSERTED I LEFT JOIN DELETED D ON I.id=D.id
where IsNull(I.field, -1) <> IsNull(D.field, -1)
END
and the code of the calls
...
insert into table ( anotherfield)
values (#anotherfield)
if ##rowcount=1 SET #ID=##Identity
...
update table
set field = #field
where Id = #ID
...
Sometimes the GetDate() between the 2 calls (insert and update) takes 7 milliseconds and sometimes it has the same value.
That's not exactly full solution but try using SYSDATETIME instead and of course make sure that target table can store up datetime2 up to microseconds.
Note that you can't force different datetime regardless of precision (unless you will start counting up to ticks) as stuff can just happen at the same time wihthin given precision.
If stretching up to microseconds won't solve the issue on practical level, I think you will have to either redesign this logging schema (perhaps add identity column on top of what you have) or add some dirty trick - like make this insert in try catch block and add like microsecond (nanosecond?) in a loop until you insert successfully. Definitely not s.t. I would recommend.
Look at this answer: SQL Server: intrigued by GETDATE()
If you are inserting multiple ROWS, they will all use the same value of GetDate(), so you can try wrapping it in a UDF to get unique values. But as I said, this is just a guess unless you post the code of your trigger so we can see what you are actually doing?
It sounds like you're trying to create an audit trail - but now you want to forge some of the entries?
I'd suggest instead adding a rowversion column to the table and including that in your uniqueness criteria - either instead of or as well as the datetime value that is being recorded.
In this way, even if two rows are inserted with identical date/time data, you can still tell the actual insertion order.
I'm currently working on a stored procedure in SQL Server 2012 using T-SQL. My problem: I have several SWOTs (e.g. for a specific client) holding several SWOTParts (strengths, weaknesses, opportunities, and threats). I store the values in a table Swot as well as in another table SwotPart.
My foreign Key link is SwotId in SwotPart, thus 1 Swot can hold N SwotParts. Hence, I store the SwotId in every SwotPart.
I can have many Swots and now need to set the SwotId correctly to create the foreign key. I set the SwotId using SCOPE_IDENTITY() unfortunately it only takes the last SwotId from the DB.I'm looking for something like a for loop to increment the SwotId after each insert on the 1st insert.
DECLARE #SwotId INT = 1;
-- 1st insert
SET NOCOUNT ON
INSERT INTO [MySchema].[SWOT]([SwotTypeId]) // Type can be e.g. a sepcific client
SELECT SwotTypeId
FROM #SWOTS
SET #SwotId = SCOPE_IDENTITY(); // currently e.g. 7, but should increment: 1, 2, 3...
-- 2nd insert
SET NOCOUNT ON
INSERT INTO [MySchema].[SwotPart]([SwotId], [FieldTypeId], [Label]) // FieldType can be e.g. Streangh
SELECT #SwotId, FieldTypeId, Label
FROM #SWOTPARTS
Do you know how to solve this issue? What could I use instead of SCOPE_IDENTITY()?
Thank you very much!
You can output the inserted rows into a temporary table, then join your #swotparts to the temporary table based on the natural key (whatever unique column set ties them together beyond the SwotId). This would solve the problem with resorting to loops or cursors, while also overcoming the obstacle of doing a single swot at a time.
set nocount, xact_abort on;
create table #swot (SwotId int, SwotTypeId int);
insert into MySchema.swot (SwotTypeId)
output inserted.SwotId, inserted.SwotTypeId into #swot
select SwotTypeId
from #swots;
insert into MySchema.SwotPart(SwotId, FieldTypeId, Label)
select s.SwotId, p.FieldTypeId, p.Label
from #swotparts p
inner join #swot s
on p.SwotTypeId = p.SwotTypeId;
Unfortunately I cant comment so I`ll leave you an answer hopefully to clarify some things:
Since you need to create the correct foreign key I don`t understand
why do you need to increment a value instead of using the id inserted
into the SWOT table.
I suggest returning the inserted id using the SCOPE_IDENTITY right after the insert statement and use it for you insert into the swot parts (there is plenty of info about it and how to use it)
DECLARE #SwotId INT;
-- 1st insert
INSERT INTO [MySchema].[SWOT]([SwotTypeId]) // Type can be e.g. a sepcific client
SET #SwotId = SCOPE_IDENTITY();
-- 2nd insert
INSERT INTO [MySchema].[SwotPart]([SwotId], [FieldTypeId], [Label])
SELECT #SwotId, FieldTypeId, Label
FROM #SWOTPARTS
I have a table which have 31 Columns
PrimaryField,PersNr, a1, a2, a3, a4, ...
in the a1 - a31 fields are values. The software generate automaticly each month one row.
The user can now from the software update a field or delete it (Update to NULL).
But now I need a Trigger which make an insert in a new table for each changed field. The Problem is the comparison from the before row and the changed row. How can I get the changed field when the User Update the Row?
Here is some code you can run that should work:
CREATE TRIGGER TriggerName --The name of your trigger
ON Table1 --The table where the update happens
AFTER UPDATE
AS
INERT INTO --you new tabe namegoes here
()--your new table fields go here
SELECT --only the fields you have in the parenthesis above in the same order
FROM Inerted I
The way most triggers are is that as soon as a value is inseted updated or deleted the trigger has a special vlaue in this case fr update and inserted actions the table is called Inserted and that will grab the most current value entered.
In a SQL Server trigger, you have access to Inserted and Deleted pseudo tables; those keep the data that has been modified: the first one stores the new values, the second the old ones.
CREATE TRIGGER [dbo].[MyTableUpdate
ON [dbo].[MyTable]
AFTER UPDATE
AS
IF ##ROWCOUNT = 0
RETURN
IF NOT UPDATE (a1) AND NOT UPDATE(a2) AND NOT UPDATE(a3) AND NOT UPDATE...
RETURN
SELECT YourCOlumns FROM Inserted
SELECT YourColumsn FROM Deleted
--Compare the values as you prefer
Thank you all for helping me.
In the morning when I stand up I got an Idea :)
The point was:
1. DECLARE AND Set Variables:
DECLARE #ai1 VARCHAR(30);
DECLARE #ad1 VARCHAR(30);
....
SET #ai1 = (SELECT a1 from inserted);
SET #ad1 = (SELECT a1 from deleted);
...
To Compare every #ai and #ad
IF NOT #ai1 = #ad1 OR (#ai1 IS NULL AND #ad1 IS NOT NULL) OR (#ai1 IS NOT NULL AND #ad1 IS NULL)
BEGIN
... Insert...
END
IF NOT #ai2 = #ad2...
Thats the Trick. But thank you all very much!!!
I am struggling to find a SQL Server replacement for select for update that works.
I have a master table that contains a column which is used for next order number. The application does a select from update on this row, reads the current value (while locked) adds one to this value and then updates the row, then uses the number it received. This process works perfectly on all databases I've tried but for SQL Server which does not seem to have any process for selecting data for exclusive use.
How do I do a locked read and update of something like a next order number from a sequence table is SQL Server?
BTW, I know I can use things like IDENTITY cols and stuff, to do this, but in this case I must read from this existing column. Get the value and inc it, and do it in a safe locked manner to avoid 2 users getting the same value.
UPDATE::
Thank you, that works for this case :)
DECLARE #Output char(30)
UPDATE scheme.sysdirm
SET #Output = key_value = cast(key_value as int)+1
WHERE system_key='OPLASTORD'
SELECT #Output
I have one other place I do something similar. I read and lock a stock record too.
SELECT STOCK
FROM PRODUCT
WHERE ID = ? FOR UPDATE.
I then do some validation and the do
UPDATE PRODUCT SET STOCK = ?
WHERE ID=?
I can't just use your above method here, as the value I update is based on things I do from the stock I read. But I need to ensure no one else can mess with the stock while I do this. Again, easy on other DB's with SELECT FOR UPDATE... is there a SQL Server workaround?? :)
You can simple do an UPDATE that also reads out the new value into a SQL Server variable:
DECLARE #Output INT
UPDATE dbo.YourTable
SET #Output = YourColumn = YourColumn + 1
WHERE ID = ????
SELECT #Output
Since it's an atomic UPDATE statement, it's safe against concurrency issues (since only one connection can get an update locks at any one given time). A potential second session that wants to get the incremented value at the same time will have to wait until the first one completes, thus getting the next value from the table.
As an alternative you can use the OUTPUT clause of the UPDATE statement, although this will insert into a table variable.
Create table YourTable
(
ID int,
YourColumn int
)
GO
INSERT INTO YourTable VALUES (1, 1)
GO
DECLARE #Output TABLE
(
YourColumn int
)
UPDATE YourTable
SET YourColumn = YourColumn + 1
OUTPUT inserted.YourColumn INTO #Output
WHERE ID = 1
SELECT TOP 1 YourColumn
FROM #Output
**** EDIT
If you want to ensure that no-one can change the data after you have read it, you can use a repeatable read. You should be aware that any reads of any tables you do will be locked for Update (pessimistic locking) and may cause Deadlocking. You can also sue the SELECT ... FROM TABLE (UPDLOCK) hint within a transaction.
SET TRANSACTION ISOLATION LEVEL REPEATABLE READ
BEGIN TRANSACTION
SELECT STOCK
FROM PRODUCT
WHERE ID = ?
.....
...
UPDATE Product
SET Stock = nnn
WHERE ID = ?
COMMIT TRANSACTION
I've got the following rough structure:
Object -> Object Revisions -> Data
The Data can be shared between several Objects.
What I'm trying to do is clean out old Object Revisions. I want to keep the first, active, and a spread of revisions so that the last change for a time period is kept. The Data might be changed a lot over the course of 2 days then left alone for months, so I want to keep the last revision before the changes started and the end change of the new set.
I'm currently using a cursor and temp table to hold the IDs and date between changes so I can select out the low hanging fruit to get rid of. This means using #LastID, #LastDate, updates and inserts to the temp table, etc...
Is there an easier/better way to calculate the date difference between the current row and the next row in my initial result set without using a cursor and temp table?
I'm on sql server 2000, but would be interested in any new features of 2005, 2008 that could help with this as well.
Here is example SQL. If you have an Identity column, you can use this instead of "ActivityDate".
SELECT DATEDIFF(HOUR, prev.ActivityDate, curr.ActivityDate)
FROM MyTable curr
JOIN MyTable prev
ON prev.ObjectID = curr.ObjectID
WHERE prev.ActivityDate =
(SELECT MAX(maxtbl.ActivityDate)
FROM MyTable maxtbl
WHERE maxtbl.ObjectID = curr.ObjectID
AND maxtbl.ActivityDate < curr.ActivityDate)
I could remove "prev", but have it there assuming you need IDs from it for deleting.
If the identity column is sequential you can use this approach:
SELECT curr.*, DATEDIFF(MINUTE, prev.EventDateTime,curr.EventDateTime) Duration FROM DWLog curr join DWLog prev on prev.EventID = curr.EventID - 1
Hrmm, interesting challenge. I think you can do it without a self-join if you use the new-to-2005 pivot functionality.
Here's what I've got so far, I wanted to give this a little more time before accepting an answer.
DECLARE #IDs TABLE
(
ID int ,
DateBetween int
)
DECLARE #OID int
SET #OID = 6150
-- Grab the revisions, calc the datediff, and insert into temp table var.
INSERT #IDs
SELECT ID,
DATEDIFF(dd,
(SELECT MAX(ActiveDate)
FROM ObjectRevisionHistory
WHERE ObjectID=#OID AND
ActiveDate < ORH.ActiveDate), ActiveDate)
FROM ObjectRevisionHistory ORH
WHERE ObjectID=#OID
-- Hard set DateBetween for special case revisions to always keep
UPDATE #IDs SET DateBetween = 1000 WHERE ID=(SELECT MIN(ID) FROM #IDs)
UPDATE #IDs SET DateBetween = 1000 WHERE ID=(SELECT MAX(ID) FROM #IDs)
UPDATE #IDs SET DateBetween = 1000
WHERE ID=(SELECT ID
FROM ObjectRevisionHistory
WHERE ObjectID=#OID AND Active=1)
-- Select out IDs for however I need them
SELECT * FROM #IDs
SELECT * FROM #IDs WHERE DateBetween < 2
SELECT * FROM #IDs WHERE DateBetween > 2
I'm looking to extend this so that I can keep at maximum so many revisions, and prune off the older ones while still keeping the first, last, and active. Should be easy enough through select top and order by clauses, um... and tossing in ActiveDate into the temp table.
I got Peter's example to work, but took that and modified it into a subselect. I messed around with both and the sql trace shows the subselect doing less reads. But it does work and I'll vote him up when I get my rep high enough.