truncate

问题 Is there a possibility to truncate with one SQL statement, multiple tables? Like this: truncate table #OBJ_AvailabilityTraining, #OBJ_AvailabilityHoliday, #Dates_temp; Regards 回答1: No, you can only truncate a single table with TRUNCATE command. To truncate multiple tables you can use T-SQL and iterate through table names to truncate each at a time. DECLARE @delimiter CHAR(1), @tableList VARCHAR(MAX), @tableName VARCHAR(20), @currLen INT SET @delimiter = ',' SET @tableList = 'table1,table2

问题 I need to empty an LDF file before sending to a colleague. How do I force SQL Server to truncate the log? 回答1: if I remember well... in query analyzer or equivalent: BACKUP LOG databasename WITH TRUNCATE_ONLY DBCC SHRINKFILE ( databasename_Log, 1) 回答2: 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

问题 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);

问题 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`

问题 I am trying to partially truncate (or shorten) an existing file, using fstream. I have tried writing an EOF character, but this seems to do nothing. Any help would be appreciated... 回答1: I don't think you can. There are many functions for moving "up and down" the wrapper hierarchy for HANDLE<->int<->FILE * , at least on Windows, but there is no "proper" to extract the FILE * from an iostreams object (if indeed it is even implemented with one). You may find this question to be of assistance.

问题 I am trying to partially truncate (or shorten) an existing file, using fstream. I have tried writing an EOF character, but this seems to do nothing. Any help would be appreciated... 回答1: I don't think you can. There are many functions for moving "up and down" the wrapper hierarchy for HANDLE<->int<->FILE * , at least on Windows, but there is no "proper" to extract the FILE * from an iostreams object (if indeed it is even implemented with one). You may find this question to be of assistance.

问题 I store my passwords in my database hashed with password_hash(), and I am trying to verify the passwords on login with password_verify(). For some reason password_verify() keeps returning false. I read the documentation on this function and it said to make sure that the hash used in the function is between single quotes ' ' otherwise it will read the hash like it is three variables because of the $'s, so i tried writing $valid like this '$valid'. But that didn't work. When I echo $valid the

问题 I am trying to truncate some long text in C#, but I don't want my string to be cut off part way through a word. Does anyone have a function that I can use to truncate my string at the end of a word? E.g: "This was a long string..." Not: "This was a long st..." 回答1: Try the following. It is pretty rudimentary. Just finds the first space starting at the desired length. public static string TruncateAtWord(this string value, int length) { if (value == null || value.Length < length || value

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: c# - How do I round a decimal value to 2 decimal places (for output on a page) I want to truncate the decimals like below i.e. 2.22939393 -> 2.229 2.22977777 -> 2.229 回答1: double d = 2.22977777; d = ( (double) ( (int) (d * 1000.0) ) ) / 1000.0 ; Of course, this won't work if you're trying to truncate rounding error, but it should work fine with the values you give in your examples. See the first two answers to

问题 Using MSSQL2005, can I truncate a table with a foreign key constraint if I first truncate the child table (the table with the primary key of the FK relationship)? I know that I can either Use a DELETE without a where clause and then RESEED the identity (or) Remove the FK, truncate the table, and recreate the FK. I thought that as long as I truncated the child table before the parent, I'd be okay without doing either of the options above, but I'm getting this error: Cannot truncate table