我们很多程序员认为临时表非常危险,因为临时表有可能被多个连接所共享.其实在SQL Server中存在两种临时表:局部临时表和全局临时表,局部临时表(Local temp table)以#前缀来标识,并且只能被创建它的连接所使用.全局临时表(Global temp table)以##前缀来进行标识,并且可以和其它连接所共享. 局部临时表 局部临时表不能够...
http://databases.aspfaq.com/database/should-i-use-a-temp-table-or-a-table-variable.htmltalks more about how to use them. And therecent articlein SQLServerCentral.com A summarization of table variable vs. temp table is attached in the appendix. Instead of repeating those well known facts, ...
Following are scenarios where temp table/variable are not cached: 1. select into #t 2. alter table #t 3. create index on #t 4. Global temp tables (##t) 5. Local temp tables on adhoc level (nest level 0) 6. table variables are also...
D. Scenario: Table variable can be MEMORY_OPTIMIZED=ON Show 4 more Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance If you use temporary tables, table variables, or table-valued parameters, consider conversions of them to leverage memory-optimized tables and table variables...
其实在SQL Server中存在两种临时表:局部临时表和全局临时表,局部临时表(Local temp table)以#前缀来标识,并且只能被创建它的连接所使用.全局临时表(Global temp table)以##前缀来进行标识,并且可以和其它连接所共享.局部临时表局部临时表不能够被其它连接所共享的原因其实是在SQL Server 2000中自动为局部临时表的表...
15. Unlike a #temp table, you cannot drop a table variable when it is no longer necessary—you just need to let it go out of scope.16. You can’t build the table variable inside dynamic SQL. This is because the rest of the script knows nothing about the temporary objects created ...
I often see that quoted as implying that there is still some memory benefit to table variables vs #temp tables however as far as I can tell the pages belonging to a table variable are always in tempdb, even if it only contains one row DECLARE @T TABLE(X INT); INSERT INTO...
Scope of table variable and temp table I have a web application that has a connection string to SQL Server with a specific database user, so anybody uses this application access database with this SQL Server user. Now, this users runs a specific stored procedure, where I have a table vari...
But, changing the length of a variable-length column used in a CHECK or UNIQUE constraint is allowed. Associated with a default definition. However, the length, precision, or scale of a column can be changed if the data type isn't changed. The data type of text, ntext, and image ...
全局临时表(Global temp table)以##前缀来进⾏标识,并且可以和其它连接所共享.局部临时表 局部临时表不能够被其它连接所共享的原因其实是在SQL Server 2000中⾃动为局部临时表的表名后⾯加上了⼀个唯⼀字符来标识.如:CREATE TABLE [#DimCustomer_test]([CustomerKey] [int]