constraints

问题 I am running an SSIS package which will replace data for a few tables from FlatFiles to existing tables in a database. My package will truncate the tables and then insert the new data. When I run my SSIS package, I get an exception because of the foreign keys. Can I disable the constraints, run my import, then re-enable them? 回答1: To disable foreign key constraints: DECLARE @sql NVARCHAR(MAX) = N''; ;WITH x AS ( SELECT DISTINCT obj = QUOTENAME(OBJECT_SCHEMA_NAME(parent_object_id)) + '.' +

问题 Could you help me frame a query that retrieves the constraints in all the tables, the count of constraints in each table, and also display NULL for tables that do NOT have any constraints. Thx in advance! This is what I have so far: Select SysObjects.[Name] As [Constraint Name] , Tab.[Name] as [Table Name], Col.[Name] As [Column Name] From SysObjects Inner Join (Select [Name],[ID] From SysObjects) As Tab On Tab.[ID] = Sysobjects.[Parent_Obj] Inner Join sysconstraints On sysconstraints.Constid

问题 Could you help me frame a query that retrieves the constraints in all the tables, the count of constraints in each table, and also display NULL for tables that do NOT have any constraints. Thx in advance! This is what I have so far: Select SysObjects.[Name] As [Constraint Name] , Tab.[Name] as [Table Name], Col.[Name] As [Column Name] From SysObjects Inner Join (Select [Name],[ID] From SysObjects) As Tab On Tab.[ID] = Sysobjects.[Parent_Obj] Inner Join sysconstraints On sysconstraints.Constid

问题 Is there a way to get the following function declaration? public bool Foo<T>() where T : interface; ie. where T is an interface type (similar to where T : class , and struct ). Currently I've settled for: public bool Foo<T>() where T : IBase; Where IBase is defined as an empty interface that is inherited by all my custom interfaces... Not ideal, but it should work... Why can't you define that a generic type must be an interface? For what it's worth, I want this because Foo is doing reflection

问题 I'm trying to place a UIImageView at the top of a UIScrollView and when I constrain the UIScrollView to the sides of the View Controller and constrain the UIImageView to the top and make the width of the UIImageView equal to the UIScrollView it makes the UIImageView way wider than the UIScrollView, and much taller than expected. Any idea what I'm doing wrong? Storyboard: Preview: 回答1: Check that following constraints are added to your view: Go to Storyboard -> Select your view Now at right

问题 I am displaying a view in the bottom of the universal application and adding this view dynamically in my view. I want to show this view in bottom every time like iAd. in both orientation. How can I add constraints for this. Please suggest. Thanks 回答1: To fix a view to the bottom of the screen you need following constraints to set. Leading Constraint with respect of Parent View for - X Trailing Constraint with respect of Parent View for - Width Bottom Constraint with respect of Parent View for

问题 I am displaying a view in the bottom of the universal application and adding this view dynamically in my view. I want to show this view in bottom every time like iAd. in both orientation. How can I add constraints for this. Please suggest. Thanks 回答1: To fix a view to the bottom of the screen you need following constraints to set. Leading Constraint with respect of Parent View for - X Trailing Constraint with respect of Parent View for - Width Bottom Constraint with respect of Parent View for

问题 I am having trouble with this table CREATE TABLE `Participants` ( `meetid` int(11) NOT NULL, `pid` varchar(15) NOT NULL, `status` char(1) DEFAULT NULL, PRIMARY KEY (`meetid`,`pid`), CONSTRAINT `participants_ibfk_1` FOREIGN KEY (`meetid`) REFERENCES `Meetings` (`meetid`) ON DELETE CASCADE CONSTRAINT `participants_ibfk_2` CHECK (status IN ('a','d','u')) CONSTRAINT `participants_ibfk_3` CHECK (pid IN (SELECT name FROM Rooms) OR pid IN (SELECT userid FROM People)) ); I want to have a foreign key

问题 I am having trouble with this table CREATE TABLE `Participants` ( `meetid` int(11) NOT NULL, `pid` varchar(15) NOT NULL, `status` char(1) DEFAULT NULL, PRIMARY KEY (`meetid`,`pid`), CONSTRAINT `participants_ibfk_1` FOREIGN KEY (`meetid`) REFERENCES `Meetings` (`meetid`) ON DELETE CASCADE CONSTRAINT `participants_ibfk_2` CHECK (status IN ('a','d','u')) CONSTRAINT `participants_ibfk_3` CHECK (pid IN (SELECT name FROM Rooms) OR pid IN (SELECT userid FROM People)) ); I want to have a foreign key

问题 I'm looking for a way to temporarily turn off all DB's constraints (eg table relationships). I need to copy (using INSERTs) one DB's tables to another DB. I know I can achieve that by executing commands in proper order (to not break relationships). But it would be easier if I could turn off checking constraints temporarily and turn it back on after the operation's finish. Is this possible? 回答1: You can disable FK and CHECK constraints only in SQL 2005+ . See ALTER TABLE ALTER TABLE foo