I have not done anything. I just run this command DELETE FROM feed_republic. But I want to get my data again. What should I do?
When I run rollback I am getting the following message. Please help!
WARNING: there is no transaction in progress
I have not used any commit or any other command unlike this question Can I rollback a transaction I've already committed? (data loss).
PostgreSQL is running in autocommit mode, so every statement is running in its own transaction unless you explicitly start a transaction with BEGIN or START TRANSACTION.
The only way you can get your data back is by restoring from a backup.
Related
I know that you do the BEGIN; command, then all commands after that can be rolled back, as long as you haven't executed COMMIT; yet. My question is, is there a command to roll back just one command and not ALL commands after the BEGIN? I'm using Postgres by the way.
Read https://www.postgresql.org/docs/14/tutorial-transactions.html about SAVEPOINT and ROLLBACK TO SAVEPOINT.
I was updating the statement in Sqlplus and not commit the code. I am using exit to the terminal.
It is a simple update statement only but I am not commit the code.
Example: I was connected to SQL Plus using username and password.
UPDATE USER SET Name='Daniel' WHERE Name='Francis';
exit
Could you please guide me How to commit in another session or
Could you please update the possible suggestion.
Thanks
USER is a reserved keyword in SQLPLUS, you should use escape character.
Commit:
set exitcommit off
UPDATE "USER" SET Name='Daniel' WHERE Name='Francis';
exit
According to the Oracle docs, at least for version 10g, if your program quits without committing (and you haven't turned on autocommit), the transaction is automatically rolled back. Transactions are isolated at the session level so it is not possible to commit from a different session.
One thing I am uncertain on is whether a DDL statement will commit from a different session. The documentation suggests that a DDL statement forces a commit but it is not clear on the behavior across sessions. Most likely, a DDL statement will be blocked by another session's transactions, but it might be worth trying out.
If you do not explicitly commit the transaction and the program
terminates abnormally, then the last uncommitted transaction is
automatically rolled back.
I have run SQL server command (update command).
the command has been performed successfully and the table has been updated
is there any way to take back in that command ?
note: no backup taken
If you had originally asked the question how do I do an UPDATE with the possibility of ROLLBACK I would tell you you should do your ad-hoc updates like this.
BEGIN TRANSACTION
UPDATE blah
SET value = newvalue
WHERE condition = someothervalue
--COMMIT TRANSACTION
Then if the results are as expected run the COMMIT TRANSACTION. If they are not than you could do a ROLLBACK TRANSACTION. However since you already did the updates and have no backups or recovery plan you are pretty much out of luck.
After you have already executed an update command the only way back would be via restoring a backup.
Something I do when writing any modification scripts is to wrap the command in a transaction and then either run a rollback or a commit depending on if the query performed as suspected.
Example:
--start the transaction only execute the first three lines, this leaves the transaction open
BEGIN TRANSACTION
UPDATE TABLEA
SET COL1 = "newValue"
--examine data and based on the results run one of these two lines
ROLLBACK TRANSACTION
COMMIT TRANSACTION
How to rollback delete command without using transaction ? if we can't , then what's the difference between Truncate & delete ?
You cannot rollback in this case, but when you are using the Full Recovery Model, then you can turn your database back to the moment before you issued the delete command.
You cannot ROLLBACK an operation without a transaction. You could probably use implicit transactions, but you still need to call COMMIT or ROLLBACK explicitly. However, for better control, it's better to wrap the statement(s) in a BEGIN TRANSACTION...COMMIT / ROLLBACK block anyway. This way you'll avoid any confusion and the need to use the IMPLICIT_TRANSACTION setting.
You can roll back DELETE or TRUNCATE (and most other operations) if and only if they are part of a transaction that's not yet committed. Alternatively you could restore the deleted/truncated data from a backup.
There are several differences between TRUNCATE and DELETE. Most notably TRUNCATE can only empty a table whereas DELETE deletes just the rows you specify. TRUNCATE deallocates and logs data at the page level instead of row level, which typically makes TRUNCATE a more efficient method than DELETE for deleting the entire content of a table.
Question:
Normally, you can undo a sql command with rollback.
BEGIN TRY
BEGIN TRANSACTION
/* run all your SQL statements */
COMMIT TRANSACTION
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION
END CATCH
My question now:
If 'one' did this
UPDATE TABLE_X SET FIELD_X = 'bla'
GO
in SSMS (notice the go at the end) and forgot to specify the WHERE clause,
is it possible (and how) to rollback the implicit transaction that SSMS executed this command in (statements with go at the end are implicitly executed in a transaction) ?
Note:
I didn't do that, but a colleague of mine did a few days ago (without go).
I undid the damage he did (fortunately I made a backup 0.5 hours before he did that), but for the future, it would be good to know this, because this happened to me once, too.
No, you can't, not easily. Restoring from backup is the best option.
see the link below, I think it will help you
How to recover the old data from table
thanks
Arun
GO does not specify the end of an implicit transaction, but the end of a batch. That's why you won't be able (unfortunately) to ROLLBACK your UPDATE after a GO.
From the MSDN page on GO:
GO is not a Transact-SQL statement; it is a command recognized by the
sqlcmd and osql utilities and SQL Server Management Studio Code
editor.
SQL Server utilities interpret GO as a signal that they should send
the current batch of Transact-SQL statements to an instance of SQL
Server. The current batch of statements is composed of all statements
entered since the last GO, or since the start of the ad hoc session or
script if this is the first GO.
The UPDATE command will only be seen as the start of an implicit transaction if you have specified SET IMPLICIT_TRANSACTIONS ON; (see here). In that case, a number of commands (CREATE, DELETE, UPDATE etcetera) will automatically start a new implicit transaction, and that transaction will not end until you issue a ROLLBACK or a COMMIT.
(See for more info on the difference between transactions and batches in SQL Server for example this question on ServerFault: SQL Server: Statements vs. Batches vs. Transactions vs. Connections.)