truncate

Can the SQL "truncate table" command be used within a transaction? I am creating an app and my table has a ton of records. I want to delete all the records, but if the app fails I was to rollback my transaction. Deleting each record takes a very long time. I'm wondering if I use truncate table, can I still rollback the transaction and get my data back in the event of a failure. I realize that truncate table doesn't write each delete to the transaction log, but I'm wondering if it writes the page deallocation to the log so that rollback works. In SQL Server, you can rollback a TRUNCATE from a

Could someone give me a quick overview of the pros and cons of using the following two statements: TRUNCATE TABLE dbo.MyTable vs DELETE FROM dbo.MyTable It seems like they both do the same thing when all is said and done; but are there must be differences between the two. dcp TRUNCATE doesn't generate any rollback data, which makes it lightning fast. It just deallocates the data pages used by the table. However, if you are in a transaction and want the ability to "undo" this delete, you need to use DELETE FROM , which gives the ability to rollback. EDIT: Note that the above is incorrect for

I need to empty an LDF file before sending to a colleague. How do I force SQL Server to truncate the log? if I remember well... in query analyzer or equivalent: BACKUP LOG databasename WITH TRUNCATE_ONLY DBCC SHRINKFILE ( databasename_Log, 1) Blorgbeard In management studio: Don't do this on a live environment, but to ensure you shrink your dev db as much as you can: Right-click the database, choose Properties , then Options . Make sure "Recovery model" is set to "Simple", not "Full" Click OK Right-click the database again, choose Tasks -> Shrink -> Files Change file type to "Log" Click OK.

Access is truncating the data in a couple Memo fields when I am appending an Excel file. The field in the Access table is already set as a Memo type. I believe the problem is that I do not have any entries in the first few rows of some of the memo fields. Access is assuming the data is a text field, even though I have already set it as a Memo type. I have tried appending as a CSV. Did not work. I have put dummy data in the first row that exceeds the 255 character limit and the data is not truncated if I do that. I do not want to have to put dummy data in every time I have to import an Excel

I have a large (multi-GB) array in Matlab, that I want to truncate¹. Naively, I thought that truncating can't need much memory, but then I realised that it probably can: >> Z = zeros(628000000, 1, 'single'); >> Z(364000000:end) = []; Out of memory. Type HELP MEMORY for your options. Unless Matlab does some clever optimisations, before truncating Z , this code actually creates an array (of type double!) 364000000:628000000 . I don't need this array, so I can do instead: >> Z = Z(1:363999999); In this case, the second example works, and is fine for my purpose. But why does it work? If Z

I've created a view which uses GROUP_CONCAT to concatenate results from a query on products column with data type of 'varchar(7) utf8_general_ci' in a column named concat_products . The problem is that mysql truncates value of concat_products column. phpMyAdmin says the data type of concat_products column is varchar(341) utf8_bin table products: CREATE TABLE `products`( `productId` tinyint(2) unsigned NOT NULL AUTO_INCREMENT, `product` varchar(7) COLLATE utf8_general_ci NOT NULL, `price` mediumint(5) unsigned NOT NULL, PRIMARY KEY (`productId`)) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET

I have a process that's writing a lot of data to stdout, which I'm redirecting to a log file. I'd like to limit the size of the file by occasionally copying the current file to a new name and truncating it. My usual techniques of truncating a file, like cp /dev/null file don't work, presumably because the process is using it. Is there some way I can truncate the file? Or delete it and somehow associate the process' stdout with a new file? FWIW, it's a third party product that I can't modify to change its logging model. EDIT redirecting over the file seems to have the same issue as the copy