I have an update statement to update some values for a table, but made a mistake. How can I roll this back?
The query I ran is this:
update t1
set t1.[DateAdded] = case
when t1.[DateAdded] is null
then cast(getdate() as date)
end
from [PEA].[pc].[TPC_Participants_Record_STG] as t1;
go
You might get away with the following update:
UPDATE [PEA].[pc].[TPC_Participants_Record_STG]
SET DateAdded = NULL
WHERE DateAdded = CAST(GETDATE() AS date);
But note carefully that the above assumes that before your erroneous update no records already had a DateAdded value with today's date. If not, then the above would be nulling out some possibly valid data which should not change.
Related
I am trying to populate a column based on a certain condition when the table is updated with new rows using trigger.
Here is what I wrote.
create trigger [myschema].[charD]
on [myschema].[deposits]
after update
as
begin
set nocount on;
update myschema.deposits
set dayC = (convert(varchar, day, 23))
from myschema.deposits
where dayC is null
end
GO
This doesn't update or populate the column dayC when new rows are added, what am I missing here?
set dayC = (convert(varchar, day, 23))
Looks like you are converting / formatting a date or datetime to string in YYYY-MM-DD format
Instead of using trigger, you can use a computed column
ALTER TABLE [myschema].[deposits]
ADD [dayc] AS CONVERT(VARCHAR(10), [day], 23)
You need to change it to after insert
Also you have no correlation to the inserted table.
You need to join with inserted on your PK to update the inserted rows, otherwise you are updating all rows in your table every time.
use-the-inserted-and-deleted-tables
I am trying to update a data type in the table I work with. It currently is stored as an int but it really is a date column.
It looks like 20191012 right now. For some reason instead of using null, they had columns with no dates be 0.
When I query the table I use
case
when bthdat = 0
then '9999-12-31'
else convert(date, convert(varchar(10), bthdat)) as dob
end
Can I use the same logic to update the actual table itself? If so, how? Thanks.
You're not going to be able to UPDATE your existing column, as int and date aren't compatible.
What you can do, however, is change the datatype a couple of times, with an UPDATE in the middle. This, however, assumes that all the values are valid (for example don't have a value like 20190229) and in the ISO format yyyyMMdd
ALTER TABLE dbo.YourTable ALTER COLUMN bthdat varchar(10);
UPDATE dbo.YourTable
SET bthdat = NULL
WHERE bthdat = '0';
ALTER TABLE dbo.YourTable ALTER COLUMN bthdat date;
You can use as follows
update
a
set
bthdat = case
when bthdat = 0 then '9999-12-31'
else convert(date,convert(varchar(10),bthdat))
end
from
YourTable as a
Do not forget to set the else for records that are not updated to keep the existing value.
Thanks for looking. I'm trying to write a SQL Server trigger that when a new record is added containing date information, will add the day of the week to the DayOfWeek column. Here's my table, with the columns in order:
Food table:
FoodName **varchar(20)**
CategoryID (FK) **int**
Price **smallmoney**
StoreID (FK) **int**
Date **datetime**
DayOfWeek **varchar(9)**
ShopperID (FK) **int**
Week **int**
Here is the trigger I've written:
-- Create a trigger to update day of the week when a record is inserted
CREATE TRIGGER DOW
ON Food
FOR INSERT
AS
BEGIN
-- Declare a variable to hold the date ID
DECLARE #dateID DATETIME
-- Get the date from the new record and store it in #dateID
SELECT #dateID = Date FROM Food
-- Insert day of the week based on the inserted date
INSERT INTO Food (DayOfWeek)
SELECT DATENAME(dw, #dateID)
END
GO
SQL Server seemed to accept the procedure, but when I ran another procedure to insert a new record, I got this error:
Msg 515, Level 16, State 2, Procedure DOW, Line 8 [Batch Start Line 21]
Cannot insert the value NULL into column 'Week', table *******; column does not allow nulls. INSERT fails.
I am not sure why this trigger is affecting the 'Week' column at all. The code should take the value entered for the Date and use the DATENAME(dw,...) function to return the day of the week, which should go into the DayOfWeek column. I've written a stored procedure that accepts a date as input and inserts the corresponding day of the week into the record, and it works just fine, but this trigger doesn't seem to want to cooperate. I'm stumped!
What your trigger does:
it fetches a Date from your table (the last one that is returned) which is not necessarily the last inserted value.
it tries to insert a new record with just the DayOfWeek of that Date specified.
it fails, because at least the Week must also be specified.
I guess that you want to update the value of the DayOfWeek for the inserted row(s) instead. To be able to do so, there must be a way to identify the row(s) that need to be updated in the Food table by knowing the values of the inserted rows. To be sure to update the correct rows, there should be a primary key that allows you to identify them. For sure you have such a primary key, and I guess that it's named FoodID, so probably you wanted to do this:
CREATE TRIGGER DOW ON Food
FOR INSERT
AS
BEGIN
SET NOCOUNT ON;
-- update the day of the week for the inserted rows
UPDATE Food
SET [DayOfWeek] = DATENAME(dw, f.[Date])
FROM Food f
INNER JOIN inserted i ON f.FoodID = i.FoodID
END
GO
There are some major problems with your trigger. In triggers, there is an inserted table (on inserts and updates) and deleted table (on deletes and updates). You should be using this table's information to know what records need updated.
This is bad because a trigger can have multiple rows
This SQL simply will not work correctly if you insert multiple rows.
DECLARE #dateID DATETIME
SELECT #dateID = Date FROM Food
This SQL is trying to insert a new row which is causing your NULL error
It is not trying to update the row you are inserting
INSERT INTO Food (DayOfWeek)
SELECT DATENAME(dw, #dateID)
It would need to be an INSTEAD OF trigger to avoid the null constraint on the column. Wolfgang's answer will still cause a null constraint error, because after triggers run AFTER the data is inserted. An INSTEAD OF trigger will run in place of the the actual insert.
CREATE TRIGGER DOW ON Food
INSTEAD OF INSERT
AS
BEGIN
SET NOCOUNT ON;
-- update the day of the week for the inserted rows
INSERT INTO Food (FoodName,CategoryID,Price,StoreID,[Date],ShopperID,[Week],[DayOfWeek])
SELECT
FoodName,CategoryID,Price,StoreID,[Date],ShopperID,[Week],DATENAME(dw, [Date]) AS [DayOfWeek]
FROM inserted
END
GO
Personally, I think storing the week and day of week is a bad idea. You already have a value that can derive that information (Date). Any time you have multiple columns that are essentially duplicate data, you will run into maintenance pain.
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 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!!!