I’m also not sure why the restriction is there. You could try sending a friendly e-mail to the designers of Java 5 Generics (chiefly Gilad Bracha and Neal Gafter). My guess is that they wanted to support only an absolute minimum of intersection types (which is what multiple bounds essentially are), to make the language … Read more
PostgreSQL doesn’t define a partial (i.e. conditional) UNIQUE constraint – however, you can create a partial unique index. PostgreSQL uses unique indexes to implement unique constraints, so the effect is the same, with an important caveat: you can’t perform upserts (ON CONFLICT DO UPDATE) against a unique index like you would against a unique constraint. … Read more
— Disable the constraints on a table called tableName: ALTER TABLE tableName NOCHECK CONSTRAINT ALL — Re-enable the constraints on a table called tableName: ALTER TABLE tableName WITH CHECK CHECK CONSTRAINT ALL ——————————————————— — Disable constraints for all tables in the database: EXEC sp_msforeachtable ‘ALTER TABLE ? NOCHECK CONSTRAINT ALL’ — Re-enable constraints for all … Read more
The SQL command is: ALTER TABLE <tablename> ADD CONSTRAINT <constraintname> UNIQUE NONCLUSTERED ( <columnname> ) See the full syntax here. If you want to do it from a Database Diagram: right-click on the table and select ‘Indexes/Keys’ click the Add button to add a new index enter the necessary info in the Properties on the … Read more
Constraints are not part of the signature, but parameters are. And constraints in parameters are enforced during overload resolution. So let’s put the constraint in a parameter. It’s ugly, but it works. class RequireStruct<T> where T : struct { } class RequireClass<T> where T : class { } static void Foo<T>(T a, RequireStruct<T> ignore = … Read more
EDIT Note that in iOS 9 this technique will become unnecessary, because a UIStackView will perform distribution automatically. I’ll add another answer explaining how that works. How to Perform Even Distribution Using Autolayout The simplest way to do this in Interface Builder alone (rather than constructing constraints in code) is to use “spacer” views: Position … Read more
A check constraint, unfortunately, cannot reference a function like SYSDATE. You would need to create a trigger that checked these values when DML occurs, i.e. CREATE OR REPLACE TRIGGER trg_check_dates BEFORE INSERT OR UPDATE ON table1 FOR EACH ROW BEGIN IF( :new.CloseDate <= SYSDATE ) THEN RAISE_APPLICATION_ERROR( -20001, ‘Invalid CloseDate: CloseDate must be greater than … Read more
There is no immediate answer; operators are static, and cannot be expressed in constraints – and the existing primatives don’t implement any specific interface (contrast to IComparable[<T>] which can be used to emulate greater-than / less-than). However; if you just want it to work, then in .NET 3.5 there are some options… I have put … Read more
With Entity Framework 6.1, you can now do this: [Index(“IX_FirstAndSecond”, 1, IsUnique = true)] public int FirstColumn { get; set; } [Index(“IX_FirstAndSecond”, 2, IsUnique = true)] public int SecondColumn { get; set; } The second parameter in the attribute is where you can specify the order of the columns in the index. More information: MSDN
The relationship between UIScrollView and auto layout is different from other aspects of auto layout. Basically, if simple auto layout were allowed to operate, nothing would scroll. For example, if a subview of the scroll view were pinned in the normal way by a constraint to 10 points from the top of the scroll view, … Read more