constraints

问题 I'm having trouble with a specific constraint I'm trying to set up on a route. My URL must look like this one: http://hostname/id-my-title-can-be-that-long where id is composed with digit only and the title is lowercase character with dashes separator. The id and the title are also separated with a dash. For example: http://hostname/123-my-title. Here's my route definition: routes.MapRoute( "Test", "{id}-{title}", new { controller = "Article", action = "Index" }, new { id = @"(\d)+", title =

问题 Using Play 2.3 (Java), I'd like to use a parameter from application.conf as a value for a constraint. Something like: public class Some { @Constraints.MaxLength(Play.application().configuration().getInt("some.text.maxlength", 1000)) public String text; } But of course I can't do this because the annotation parameter must be a constant. What would be the approach, in Java, to bypass this? Should I use a custom validator? Or is there another option? Any help appreciated. 回答1: As you discovered

问题 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

问题 I am trying to create a simple database where I have a table of customer data and a table of order data. I am trying to write a constraint that makes it so a customer can't order more than a specific amount of items on a given day. Here's what I have: CREATE TABLE CUSTOMER ( CUSTOMER_NUM CHAR(3) PRIMARY KEY, CUSTOMER_NAME CHAR(35) NOT NULL, STREET CHAR(15), CITY CHAR(15), STATE CHAR(3), ZIP CHAR(5), ); CREATE TABLE ORDERS ( ORDER_NUM CHAR(5) PRIMARY KEY, ORDER_DATE DATE, CUSTOMER_NUM CHAR(3),

问题 what I am trying to do is have an large image contained within a smaller div that the user can drag around within the containing div (easy enough)... similar to http://oneblackbear.com/draggable/index.html but I want to prevent users from dragging it any further then the container boundary. With the above example the user can drag the image completely outside of the containing div... I want to prevent the user from ever dragging the image outside of the parent div at all. I have tried using

问题 I'm having a heck of a time figuring out how to properly implement my 404 redirecting. If I use the following <HandleError()> _ Public Class BaseController : Inherits System.Web.Mvc.Controller ''# do stuff End Class Then any unhandled error on the page will load up the "Error" view which works great. http://example.com/user/999 (where 999 is an invalid User ID) will throw an error while maintaining the original URL (this is what I want) However. If someone enters http://example.com/asdfjkl

问题 Here's the scenario: I've written some code with a type signature and GHC complains could not deduce x ~ y for some x and y . You can usually throw GHC a bone and simply add the isomorphism to the function constraints, but this is a bad idea for several reasons: It does not emphasize understanding the code. You can end up with 5 constraints where one would have sufficed (for example, if the 5 are implied by one more specific constraint) You can end up with bogus constraints if you've done

问题 I'm writing some software that requires storing items in a database, the items need to have a 'priority' so we end up with ID | Name | Priority --------+--------------+---------- 1 | Pear | 4 2 | Apple | 2 3 | Orange | 1 4 | Banana | 3 So now, the top priority fruit is the Orange, then Apple then Banana then Pear. Now, I want to make Pear the number one priority so Pear, Orange, Apple, Banana. The table will look like: ID | Name | Priority --------+--------------+---------- 1 | Pear | 1 2 |

问题 Goal: Estimate sigma1 and sigma2 with the "optim" function, while sigma2 must be greater than sigma1 Simulate data (y) I have the following kind of data y: N<-50 delta<-matrix(rep(0, N*N), nrow=N, ncol=N) for(i in 1:(N )){ for (j in 1:N) if (i == j+1 | i == j-1){ delta[i,j] <- 1; } } sigma1<-5 sigma2<-10 diagonal=2*sigma1^2+sigma2^2 nondiag<--sigma1^2*delta Lambda_i<-(diag(diagonal,N)+-nondiag)/diagonal sig<-as.matrix(diagonal*Lambda_i) sig mu<-rep(0, N) y<-as.vector(mvnfast::rmvn(1,mu, sig))

问题 I have a view on top of my viewcontroller, its height is 64. I need this view stays same size in all screen size 3.5" , 4" , 4,7" and 5,5". The result I am taking is as in screenshots. What should I do? After fixing height to 64 it looks like this ; 回答1: Add Fixed Height to your Headerview like this , check in below image . 回答2: Fix Height of your view Leading : 0 Top : 0 trailing : 0 回答3: Pin the height for wAny hAny size classes. 来源： https://stackoverflow.com/questions/36789023/uistoryboard