constraints

I am displaying a view in the bottom of the universal application and adding this view dynamically in my view. I want to show this view in bottom every time like iAd. in both orientation. How can I add constraints for this. Please suggest. Thanks To fix a view to the bottom of the screen you need following constraints to set. Leading Constraint with respect of Parent View for - X Trailing Constraint with respect of Parent View for - Width Bottom Constraint with respect of Parent View for - Y Height Constraint attached to self for - Height . Lets add. UIView *subView=bottomView; UIView *parent

Why doesn't a TRUNCATE on mygroup work? Even though I have ON DELETE CASCADE SET I get: ERROR 1701 (42000): Cannot truncate a table referenced in a foreign key constraint ( mytest . instance , CONSTRAINT instance_ibfk_1 FOREIGN KEY ( GroupID ) REFERENCES mytest . mygroup ( ID )) drop database mytest; create database mytest; use mytest; CREATE TABLE mygroup ( ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY ) ENGINE=InnoDB; CREATE TABLE instance ( ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY, GroupID INT NOT NULL, DateTime DATETIME DEFAULT NULL, FOREIGN KEY (GroupID) REFERENCES mygroup(ID) ON DELETE

I have a field that stores product codes. The codes are unique, but some products simply doesn't have a code. I can't invent codes because those are providers codes. Is this kind of constraint possible in MySQL? I'm a noob with stored procedures and triggers, so if the solution involves one of these, please be patient. Update: The column is NOT Null. That's why I was unable to do this. Yes, you can do this. See the MySQL reference (version 5.5) . A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value