How can a not null constraint be dropped?
I would try something like this ALTER TABLE testTable MODIFY COLUMN colA int;
constraints
How can I create a SQL unique constraint based on 2 columns?
You can try this: CREATE UNIQUE CLUSTERED INDEX index_name ON TABLE (col1,col2) or CREATE UNIQUE NONCLUSTERED INDEX index_name ON TABLE (col1,col2) or ALTER TABLE [dbo].[TABLE] ADD CONSTRAINT UNIQUE_Table UNIQUE CLUSTERED ( col1, col2 ) ON [PRIMARY]
Generic constraints, where T : struct and where T : class
Constraints are not part of the signature, but parameters are. And constraints in parameters are enforced during overload resolution. So let’s put the constraint in a parameter. It’s ugly, but it works. class RequireStruct<T> where T : struct { } class RequireClass<T> where T : class { } static void Foo<T>(T a, RequireStruct<T> ignore = … Read more
How do I DROP a constraint from a sqlite (3.6.21) table?
SQLite does not (as of this answer) support the alter table drop constraint command. The allowed syntax can be seen here. You will need to create a new table without a constraint, transfer the data, then delete the old table. I think something like the following should work: CREATE TABLE child2 ( id INTEGER PRIMARY … Read more
Can there be constraints with the same name in a DB?
No – a constraint is a database object as well, and thus its name needs to be unique. Try adding e.g. the table name to your constraint, that way it’ll be unique. CREATE TABLE BankAccount ( BankAccountID INT PRIMARY KEY, EmployerCode VARCHAR(20) NOT NULL, Amount MONEY NOT NULL, CONSTRAINT FK_BankAccount_Employer FOREIGN KEY (EmployerCode) REFERENCES Employer … Read more
Auto Layout to dynamically size uilabel width
Create the 1 point horizontal space between the labels: Control-drag from label2 to label1. Choose Horizontal Spacing from the pop-up. Double click the constraint. Change the constant to 1. Give label1 a max width: Select label1. Go to the top menu bar, select Editor > Pin > Width. Double click the constraint. Change the relationship … Read more
Auto Layout (Constraints) Center 2 side by side views in a parent view
Is this what you’re after? I did it by adding a view (named viewCenteredInLeftSection) within your leftSection, then adding the clock image and label as subviews with these constraints: Make viewCenteredInLeftSection‘s CenterX and CenterY equal to its superview’s (leftSection). Make clockImage‘s Top, Bottom, and Leading edges equal to its superview’s (viewCenteredInLeftSection). Make label‘s Trailing edge … Read more
Difference between NSLayoutAttributeLeft vs NSLayoutAttributeLeading
“Leading” does not always mean “Left”. For RTL-written languages (locales) leading edge of the object’s alignment rectangle will be located at the right side of the object. Quote from Auto Layout Guide: The attributes leading and trailing are the same as left and right for left-to-right languages such as English, but in a right-to-left environment … Read more
What do the letter codes in Oracle user_contraints table’s constraint_type column stand for?
From the 12cR1 documentation: C – Check constraint on a table P – Primary key U – Unique key R – Referential integrity V – With check option, on a view O – With read only, on a view H – Hash expression F – Constraint that involves a REF column S – Supplemental logging
Annotations from javax.validation.constraints not working
For JSR-303 bean validation to work in Spring, you need several things: MVC namespace configuration for annotations: <mvc:annotation-driven /> The JSR-303 spec JAR: validation-api-1.0.0.GA.jar (looks like you already have that) An implementation of the spec, such as Hibernate Validation, which appears to be the most commonly used example: hibernate-validator-4.1.0.Final.jar In the bean to be validated, … Read more