Check constraint validation attribute convention

[AndriySvyryd]

Suggested by @bricelam:

Attribute	Expression
[Compare("Y")]	X == Y
[MinLength(8)]	X.Length >= 8
[Range(0, 10)]	X >= 0 && X <= 10
[RegularExpression("[0-9A-F]+")	Regexp.IsMatch(X, "[0-9A-F]+")
[DataType(...)]	(predefined regular expressions)

[nphmuller]

If this enhancement was implemented, would the following case be supported?

When I add the [Range(0, 10)] attribute to my model, the following migration SQL statements will be generated:

ALTER TABLE MyModel
ADD CONSTRAINT CK_Table_Column_Range CHECK (
   Column >= 0 AND Column <= 10
)

[AndriySvyryd]

@nphmuller Yes, that's how it would work. Though you might need to enable the convention first.

[ajcvickers]

Notes from triage:

• We should make sure if we do this that it doesn't cause unwanted breaking change or perf impact.
• Could apply to reverse-engineering or creating migrations.

[roji]

Would we simply do this in the external check constraint plugin instead? See efcore/EFCore.CheckConstraints#5

[roji]

Closing, to be done as part of an external plugin (efcore/EFCore.CheckConstraints#5)