constraints

问题 If I have a 4x1 Cell structure with that represents a=[A1 A2 A3 A4] : a=cell(4,1) a{1}=[1 3 1 0] a{2}=[3 3 3 3] a{3}=[3 2 3 2] a{4}=[3 3 3 2] B=[1 1 1 2]; %priority I would like to do the following : Pick cells that correspond to priority B=[1 1 1 2] (where B=1 is highest priority and A=3 ) Which means, find any cell that begins with [3 3 3 #], where all their priority is 1's in B . ideal answer should be : a{2} = [3 3 3 3] and a{4} = [3,3,3,2] My try is to add this : [P arrayind]=min(B) %

问题 Rules (Transact-SQL)[1] are reusable what permitted to overcome the shortcoming of non-re-usability of check constraints. And now I read [1] that: "This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature. We recommend that you use check constraints instead. Check constraints are created by using the CHECK keyword of CREATE TABLE or ALTER TABLE" So, what is

问题 Rules (Transact-SQL)[1] are reusable what permitted to overcome the shortcoming of non-re-usability of check constraints. And now I read [1] that: "This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature. We recommend that you use check constraints instead. Check constraints are created by using the CHECK keyword of CREATE TABLE or ALTER TABLE" So, what is

问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: No type inference with generic extension method Consider two methods: public static IEnumerable<V> Merge<V> (this IEnumerable<IEnumerable<V>> coll) public static IEnumerable<V> Merge<T, V> (this IEnumerable<T> coll) where T : IEnumerable<V> Both compile just fine, in both cases the type of generic types will be known at compile time of caller, and thus the exact type of extended type. You can call both fine, but

问题 I noticed certain button sizes look great on one the iPhone 5 simulator but do not look as good on the iPhone 6 simulator and this is because the heights or constraints that I place on the UIButtons end up leaving a lot of blank space down the bottom of my App Screen. I would like to have a button that is 40% of the screen size regardless of what device I am simulating on. Any ideas on how to make the size of the button stay 40% of the screen size regardless of the device? 回答1: Ctrl drag from

问题 I have not found any answer regarding my question, all unique constraint questions did not involve MS Access. The question is how to make a unique constraint on multpile fields in MS Access 2003 database? If my table consists of columns id, A, B, C, D, E, F . I have an index on column id , but I would like to have a unique constraint set on both columns A and B . Hence, I may have a duplicate value in column A , provided the value in column B are different. I want to stress that I am not

问题 I am working on an ios application. I am adding the auto-layout programmatically to 2 labels. I need to add a constraint to make them equal width. I know how to fix the width of a label by using : constraint = [NSLayoutConstraint constraintWithItem:myLabel attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:200.0f]; That would fix the label size to a constant. But I have 2 labels and I want them to

问题 Given this example (DUP_VAL_ON_INDEX Exception), is it possible to capture the values that violated the constraint so they may be logged? Would the approach be the same if there are multiple violations generated by a bulk insert? BEGIN -- want to capture '01' and '02' INSERT INTO Employee(ID) SELECT ID FROM ( SELECT '01' ID FROM DUAL UNION SELECT '02' ID FROM DUAL ); EXCEPTION WHEN DUP_VAL_ON_INDEX THEN -- log values here DBMS_OUTPUT.PUT_LINE('Duplicate value on an index'); END; 回答1: Ideally,

问题 How can I modify the multiplier of a constraint programmatically? I have set the following: [self.view addConstraint:[NSLayoutConstraint constraintWithItem:_button attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeWidth multiplier:0.5 constant:0.0]]; and I need to modify it to this: [self.view addConstraint:[NSLayoutConstraint constraintWithItem:_button attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self.view

问题 So I'm new to the constraints. I've a nib file which contains multiple Views as siblings. The ViewController's view contains a tableView and I've another view which is going to be added to the tableHeaderView (let's call it self.tableHeaderView). The problem i'm facing is that I want to resize the self.tableHeaderView based on certain conditions. I've added constraints to all of my UI elements and I can't, for whatever reason, add a height constraint to the self.tableHeaderView via the nib. I