I have "Order" table with more than 5,000 records. When I ran the update query unfortunately I forgot to give the ‘where’ condition.
Now the Date column in all the records has been updated. Is it possible to retrieve my existing column values.
Example:
Update Order
set ordered = getdate()
where Cusid=50
(here I forget to mention the where condition).
I am afraid NO, cause the update has already been committed. Unless you have a backup of the table it's no more can be undone.
Related
I have a problem with data in Oracle database:
I want to get created time of some record in table. I can get ora_rowscn of the record, but I cannot run to change this ora_rowscn to timestamp by query SELECT SCN_TO_TIMESTAMP(ora_rowscn) because SCN_TO_TIMESTAMP() may not be available for older data (my data was inserted about 1 month ago).
Anyone have solution to resolve this problem for me to get created time?
Perhaps the best thing to do here, assuming you have a long term need for this requirement, would be to alter your current table and add a bona-fide timestamp column. You could give this timestamp column a default value of the current timestamp, e.g.
CREATE TABLE yourTable (
...
created_time TIMESTAMP(6) default CURRENT_TIMESTAMP
);
Then, when inserting a new record, omit mention of the created_time column, letting Oracle back fill it with the current timestamp.
To make a long story short, is it possible to replicate rows of a table in SQL server with horizontal filtering function that being evaluated continuously?
For instance, I need to replicate a table rows to subscriber which are created or updated since last two days or more. I need any rows that are being created in source table but their creation date is older than two days get replicated to subscriber and this get done continuously on any newly created/updated rows. I mean that I don't need to replicate records that are newer than two days.
I have tried transaction replication with filtering function on SQL server 2017, but filtering function just get evaluated on replication creation time and after that, any new rows didn't get propagated to subscriber.
Add a column to your table: Alter Table yourTable Add Old_Enough Bit Not Null Default 0
Create a job that runs regularly (e.g. hourly) and runs Update yourTable Set Old_Enough = 1 Where Old_Enough = 0 And DateAdd(Day, 2, yourCreationDateColumn) < GetDate()
Create an indexed view that takes Select ... From yourTable Where Old_Enough = 1
Replicate your indexed view
I need a column to be dynamic as such that a column DaysToExpiration is calculated based on the number of days between now and a date column Expiration Date.
My plan was to add a trigger that fires on a SELECTstatement of the table.
Is this possible? How?
Is there a better way to go about this?
You say "My plan was to add a Trigger that Fires on a SELECT statement of the table."
In that case why have a column at all, why not just select it in your final query?
Select DateDiff(day,getdate(),ExpirationDate) AS [DaysToExpiration]
If it must be persisted and stored in a column then you can make it a computed column as suggested in the comments. Or you could have the table trigger on UPDATE/INSERT so when the ExpirationDate is inserted or updated it sets the DaysToExpiration column to the result of the provided code.
No there is no provision of having trigger on SELECT operation. You can use stored procedure which takes parameters that are fetched from SELECT query and call this procedure after desired SELECT query.
I have a SQL Server 2008 table with 80,000 rows and am executing the following query:
UPDATE dbo.TableName WITH (ROWLOCK)
SET HelloWorldID = NULL
WHERE HelloWorldID = #helloWorldID
HelloWorldID is an int and the #helloWorldID parameter is also int.
The query is taking too long and I'd like to optimize it. I created a nonclustered index on HelloWorldID but it didn't matter. I may have to redesign this...maybe put the HelloWorldID on another table that links it to the TableName table?
Since the command you're waiting on is DELETE I have to guess that there is a trigger on dbo.TableName and that it is performing additional work that you do not expect. Or perhaps some CASCADE option that is affecting other tables that have triggers on them.
It all depends on how much rows will be updated by this query.
If you're updating a lot of rows, say 30% of the table, then the index will actually slow down the query (as index will be updated along with the table, and it won't help with filtering the rows for update). Also ROWLOCK will slow it down, because the engine will issue a separate lock for each row (as opposed to pagelocks that would occur normally).
Try removing the index and running this update using WITH(TABLOCK) just to see what happens.
I get this problem sometimes. Your query is dependent upon simultaneously getting a write-lock on every row in the table meeting the conditions of the WHERE-Clause . Depending on your needs for full 'ACID', you could do something like this:
SELECT getdate() -- force ##rowcount=1
while ##rowcount > 0
UPDATE TOP (1000) dbo.TableName
SET HelloWorldID = NULL
WHERE HelloWorldID = #helloWorldID
This will do the update is smaller chunks, and help overcome locking issues. But remember, this-method gives up on doing this-query as a single-transaction. You will need to tune the 1000 to a value that is right for your server.
I am using SQL Server 2012
I have a table called AMOUNTS and a table called AMOUNTS_HIST
Both tables have identical columns:
CHANGE_DATE
AMOUNT
COMPANY_ID
EXP_ID
SPOT
UPDATE_DATE [system date]
The Primary Key of AMOUNTS is COMPANY_ID and EXP_ID.
The Primary Key pf AMOUNTS_HIST is COMPANY_ID, EXP_ID and CHANGE_DATE
Whenever I add a row in the AMOUNTS table, I would like to create a copy of it in the AMOUNTS_HIST table. [Theoretically, each time a row is added to 'AMOUNTS', the COMPANY_ID, EXP_ID, CHANGE_DATE will be unique. Practically, if they are not, the relevant row in AMOUNTS_HIST would need to be overridden. The code below does not take the overriding into account.]
I created a trigger as follows:
CREATE TRIGGER [MYDB].[update_history] ON [MYDB].[AMOUNTS]
FOR UPDATE
AS
INSERT MYDB.AMOUNTS_HIST (
CHANGE_DATE,
COMPANY_ID,
EXP_ID,
SPOT
UPDATE_DATE
)
SELECT e.CHANGE_DATE,
e.COMPANY_ID,
e.EXP_ID
e.REMARKS,
e.SPOT,
e.UPDATE_DATE
FROM MYDB.AMOUNTS e
JOIN inserted ON inserted.company_id = e.company_id
AND inserted.exp_id=e.exp_id
I don't understand why it does nothing at all in my AMOUNTS_HIST table.
Can anyone help?
Thanks,
Probably because the trigger, the way it's currently written, will only get fired when an Update is done, not an insert.
Try changing it to:
CREATE TRIGGER [MYDB].[update_history] ON [MYDB].[AMOUNTS]
FOR UPDATE, INSERT
I just wanted to chime in. Have you looked at CDC (change data capture).
http://msdn.microsoft.com/en-us/library/bb522489(v=sql.105).aspx
"Change data capture is designed to capture insert, update, and delete activity applied to SQL Server tables, and to make the details of the changes available in an easily consumed relational format. The change tables used by change data capture contain columns that mirror the column structure of a tracked source table, along with the metadata needed to understand the changes that have occurred.
Change data capture is available only on the Enterprise, Developer, and Evaluation editions of SQL Server."
As far as your trigger goes, when you update [MYDB].[AMOUNTS] does the trigger throw any errors?
Also I believe you can get all your data from Inserted table without needed to do the join back to mydb.amounts.