constraints

问题 Inspired by Phil Haack's attempt on null or empty coalescing, I'm trying to write a couple of extension methods for the string object, as well as on the IEnumerable<T> interface, to simplify null or emtpy ckecking. However, I'm running into problems: when I'm attempting to call the string version of AsNullIsEmpty , the compiler treats my string as an IEnumerable<char> , and of course gives the wrong return type. Is there any way to put an "anti-constraint" on the definition of the IEnumerable

问题 Really hate to use other people's time, but it seems the problem is just not going away. I considered all recommendations at http://verysimple.com/2006/10/22/mysql-error-number-1005-cant-create-table-mydbsql-328_45frm-errno-150/ and at http://forums.mysql.com/read.php?22,19755,19755#msg-19755 but nothing. hope that someone points to a stupid mistake. here are the tables: CREATE TABLE IF NOT EXISTS `shop`.`category` ( `id` INT(11) NOT NULL AUTO_INCREMENT , `category_id` INT(11) NOT NULL ,

问题 I maintain a product that is installed at multiple locations which as been haphazardly upgraded. Unique constraints were added to a number of tables, but I have no idea what the names are at any particular instance. What I do know is the table/columnname pair that has the unique constraints and I would like to write a script to delete any unique constraint on these column/table combinations. This is SQL Server 2000 and later. Something that works on 2000/2005/2008 would be best! 回答1: This

问题 I'm working on an application that will be primarily served as an API (other than a few minor views, such as session/registration, which will be "standard"). I like the approach that was finalized in Railscast #350: Versioning an API, and so followed it. My routes look like: namespace :api, :defaults => {:format => 'json'} do scope :module => :v1, :constraints => ApiConstraints.new(:version => 1, :default => false) do resources :posts, :only => [:create, :show, :destroy, :index] end scope

问题 I'm adding a view from a xib file to a table view controller and then placing this out of view so that when the user taps a button the view scrolls down from under the navigation bar to be visible. Here's the view that drops down: This works fine on iPhone 6 but anything smaller and the drop down view loses its constraints and looks all jumbled up like below: I believe this is the case because there are no constraints being set between the drop down view and the table view (the superview). I

问题 I have to implement randomize() function in systemVerilog because the tool I use (model sim) doesn't support this function. I implemented a basic function in a class with the following member: bit [15:0] data_xi; bit [15:0] data_xq; the basic random function: //function my_randomize function int my_randomize(int seed); int temp1, temp2; temp1 = (($urandom(seed)) + 1); data_xi = temp1 - 1; temp2 = (($urandom(seed)) + 1); data_xq = temp2 - 1; if(temp1 != 0 || temp2 != 0 ) return 1; else return

问题 I am trying to model a problem with Choco to get the combinations of possible matchups in a tennis event (or any sport). The way I am trying to do it I have the following: // Set of timeslots when the event is held (i.e. 10am-10pm) int nTimeslots = 12; // Courts available: court #1, #2 and #3 int nCourts = 3; String[] players = { "Novak", "Andy", "Roger", "Stan", "Rafel", "Kei", "Tomas", "David" }; int nPlayers = players.length; // Timeslots when each player cannot play for whatever reason

问题 I have set my postgres database populated and all constraints applied. I ran cake bake all on all tables and start to test. I got this error: Error: SQLSTATE[23505]: Unique violation: 7 ERROR: duplicate key value violates unique constraint "fasciculos_pkey1" DETAIL: Key (id)=(7) already exists. SQL Query: INSERT INTO "xconv2"."fasciculos" ("created", "user_id", "revista_id", "volume", "issue", "svol", "snum", "issuedate", "scheme", "reftype", "cliente_id", "output_packtype", "modified")

问题 I am trying to make the Layout using constraints, but I have many custom controls with internal nested Subviews. And I am adding the constraints to the top view (CustomView) but its not lay-outing the subviews properly. Ex. I have TextFieldWithLabel class which shows the Label on top and below that a UITextField I am creating the instance of TextFieldWithLabel and adding to super view with constraints. But its not showing the results as expected. though its visible but not placed where I

问题 I have a UIImageView , and a series of conflicting constraints set on it. I set the active property of some of them to true or to false at different times, and it works—the image view is always where it's supposed to be. However, in another method, I use it's frame to calculate the position of another view, and so I noticed that it's frame isn't where the image view appears. For example, the image view appears centered in the middle of the screen, but it's frame (I created another UIView and