constraints

I have the following unique constraint dup_Checklist_QNum UNIQUE (QUESTION_NO, IS_ACTIVE) I am trying to prevent two questions having the same question number while being active (IS_ACTIVE value = 1). All seemed fine until I had to rev a question for the second time. QUESTION_NO=1, TEXT="Have you..", REV=1, IS_ACTIVE=0 QUESTION_NO=1, TEXT="Have you..", REV=2, IS_ACTIVE=0 <-- This should be ok but constraint was violated QUESTION_NO=1, TEXT="Have you..", REV=3, IS_ACTIVE=1 QUESTION_NO=1, TEXT="Have you..", REV=3, IS_ACTIVE=1 <-- This should be throw constraint exception I need the constraint to

The code below shows a generic class with a type constraint ( Pub<T> ). The class has an event that it can raise allowing us to pass a message to subscribers. The constraint is that the message must implement IMsg (or inherit from IMsg when it's is an abstract class). Pub<T> also provides a Subscribe method to allow objects to subscribe to the notify event if and only if the object implements IHandler<IMsg> . Using .NET 4, the code below shows an error on baseImplementer.NotifyEventHandler stating that: "No overload for 'IHandler<IMsg>.NotifyEventHandler(IMsg)' matches delegate 'System.Action

When defining a generic type parameter's constraints, we have to put class() at the front and new() at the end, for example. Why is this, why can't I put my constraints in any order? Are there any other restrictions on ordering besides class / struct first, new() at the end? Example: protected T Clone<T>() where T : class, ICopyable<T>, new() Eric Lippert There's no particular reason why that order was chosen. The chosen order goes from more general to more specific, which I suppose is a reasonably nice property. As for the question "why require an order at all?", it's simply easier on the

Here's what I'd like to do: class A { String string static constraints = { string(maxSize:100) } } class B extends A { static constraints = { string(url:true) } } So class A should have some constraints and B should have the same plus additional constraints on the same property. I couldn't get that to work though and I can imagine that it would clash with the Table-per-Hierarchy concept. So I tried to work around that problem by introducing a Command object with class B's constraints which can be validated in the constructor of class B. However it seems that Command objects can only be used

autolayout自动布局技术在iOS6就已经推出了，但是因为很多人一开始不习惯使用xib编程，而是坚持使用代码布局控件，所以autolayout并没有普及的太快。但是现在随着越来越多的人开始使用xib，怎样适配不同屏幕的尺寸和横竖屏，成了亟待解决的问题，好在两年前就已经推出并且日臻完善的xib autolayout技术可以完美的解决。 首先需要说下需求：需要登陆LoginViewController视图View上面的控件居中显示。 下面我就以一个简单的例子，来简要说明使用autolayout的小技巧， （1）拖拉一个View到LoginViewController.xib的视图上面，调整高度为300，我下面都称其为MiddleView吧，如下图所示， 为了让图片垂直 居中 显示，我们可以通过键盘的上（↑）下（↓）按键移动View。 （2）拖两个UITextField和一个UIButton到View上面，同时设置了MiddleView的背景色为LightGray，如下图所示， （3）给MiddleView添加约束，使其水平和竖直居中，先选中MiddleView，然后按照下图操作， （4）给MiddleView添加宽高（width and height）的约束，上面仅仅添加水平和垂直居中，会有警告，这是因为添加的约束还不够，如下图所示，添加宽高的约束， （5

Here's the code (I'm sorry if it's so long, but it was the first example I had); I'm using the CVaR example from CreditMetrics package by A. Wittmann and DEoptim solver to optimize: library(CreditMetrics) library(DEoptim) N <- 3 n <- 100000 r <- 0.003 ead <- rep(1/N,N) rc <- c("AAA", "AA", "A", "BBB", "BB", "B", "CCC", "D") lgd <- 0.99 rating <- c("BBB", "AA", "B") firmnames <- c("firm 1", "firm 2", "firm 3") alpha <- 0.99 # correlation matrix rho <- matrix(c( 1, 0.4, 0.6, 0.4, 1, 0.5, 0.6, 0.5, 1), 3, 3, dimnames = list(firmnames, firmnames), byrow = TRUE) # one year empirical migration