constraints

Lets suppose I have a scenario with the following model: An Animal table which represents any animal, a Dog table and a Bird table, each one with a 1:1 relationship with the Animal table. Animal INTEGER id (PK) STRING name Bird INTEGER id (PK FK referencing `Animal.id`) Dog INTEGER id (PK FK referencing `Animal.id`) (I'm giving only the keys just to be clear) How can I guarantee that a given row in the Animal table will have JUST one referenced row in either the Dog or the Bird table? The model itself allows it... An animal can't be a Dog and a Bird at the same time ( not in mythology but that

I'm coming from the Asp.net MVC world where route constraints are really useful. I'm currently developing an Angular JS SPA that incorporates client side routing. I would also like to add parameter constraints to my client-side routes as in: $.routeProvider.when("/post/:id/:name?") where I'd like to constrain my :id parameter to only be valid when these are numbers. I haven't found anything similar in Angular Docs (which are horrible to say the least). Can it be done? And maybe also parameter defaults? There's no built-in way to set route constraints, but you can do it pretty easily yourself

In short, I have to generate a constrained delaunay triangulation from a set of 2D points that carry additional information. Since there could be intersecting constraints, I need that the triangulation properly interpolates the satellite data whenever it generates the new point of intersection. I tried with CGAL (C++) to define a custom kernel following the example here , but I've failed to compile it succesfully, basically because there is something fundamental of the underlying generic programming machinery of CGAL that I am missing (lot of type mismatches etc.). Can you point me to a

I have a view that has a lot of subviews, I will refer to these views as superview, subview A, subview B, subview C, etc. So I need to access the trailing space constraint I set on subView A to superview and modify it. This constraint would appear in superview.constraints. However, all the subviews have leading/trailing space constraints set between them and the superview. So, if I log superview.constraints, it would look like this: <__NSArrayM 0xac744e0>( <NSLayoutConstraint:0x98f3500 H:|-(0)-[UILabel:0x98f2190] (Names: '|':HeaderReusableView:0x98f1f40 )>, <NSLayoutConstraint:0x98f3540 H:

A quick SQLAlchemy question... I have a class "Document" with attributes "Number" and "Date". I need to ensure that there's no duplicated number for the same year , is there a way to have a UniqueConstraint on "Number + year(Date)"? Should I use a unique Index instead? How would I declare the functional part? (SQLAlchemy 0.5.5, PostgreSQL 8.3.4) Thanks in advance! Ants Aasma You should use a functional unique index to apply this constraint. Unfortunately the database generic database independent schema definition machinery in SQLAlchemy doesn't abstract functional indexes yet. You'll have to

I have this table: CREATE TABLE [tblExample]( [ExampleID] [int] IDENTITY(1,1) NOT NULL, [WordsAndStuff] [nvarchar](max) NOT NULL, [Active] [bit] NOT NULL I want the Active column to have a unique constraint that will only allow one record to be true (1). At this point, I don't need there to BE a true record all the time, there just cannot be more than one of them. How do I write the constraint? Just one active record at a time in the table? You can use a unique index with a filter: create unique nonclustered index uixf_tblExample_Active_filtered on tblExample (Active) include (ExampleId,

I want to constrain a SQL Server decimal column to only allow -1,0,1 as valid values. Can you show me the SQL syntax for adding such a constraint. (I would like to know how to do it in both the CREATE TABLE statement and/or the ALTER TABLE ADD CONSTRAINT). Or can this only be accomplished in a trigger? gbn CREATE TABLE foo ( bar int NOT NULL CONSTRAINT CK_foo_bar CHECK (bar IN (-1, 0, 1)) ) or ALTER TABLE foo WITH CHECK ADD --added WITH CHECK CONSTRAINT CK_foo_bar CHECK (bar IN (-1, 0, 1)) --not needed "FOR bar" Edit: thoughts... why constrain a decimal? Can you change it to smallint or int?