Class: DataMapper::Property::UUID

Inherits:
String
  • Object
show all
Defined in:
lib/dm-types/uuid.rb

Overview

UUID Type First run at this, because I need it. A few caveats:

* Only works on postgres, using the built-in native uuid type.
  To make it work in mysql, you'll have to add a typemap entry to
  the mysql_adapter. I think. I don't have mysql handy, so I'm
  not going to try. For SQLite, this will have to inherit from the
  String primitive
* Won't accept a random default, because of the namespace clash
  between this and the UUIDtools gem. Also can't set the default
  type to UUID() (postgres-contrib's native generator) and
  automigrate, because auto_migrate! tries to make it a string "UUID()"

Feel free to enchance this, and delete these caveats when they’re fixed.

-- Rando Sept 25, 08

Actually, setting the primitive to “UUID” is not neccessary and causes a segfault when trying to query uuid’s from the database. The primitive should be a class which has been added to the do driver you are using. Also, it’s only neccessary to add a class to the do drivers to use as a primitive when a value cannot be represented as a string. A uuid can be represented as a string, so setting the primitive to String ensures that the value argument is a String containing the uuid in string form.

<strike>It is still neccessary to add the UUID entry to the type map for each different adapter with their respective database primitive.</strike>

The method that generates the SQL schema from the typemap currently ignores the size attribute from the type map if the primitive type is String. The causes the generated SQL statement to contain a size for a UUID column (e.g. id UUID(50)), which causes a syntax error in postgres. Until this is resolved, you will have to manually change the column type to UUID in a migration, if you want to use postgres’ built in UUID type.

-- benburkert Nov 15, 08

Instance Method Summary collapse

Instance Method Details

#dump(value) ⇒ Object 



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# File 'lib/dm-types/uuid.rb', line 56

def dump(value)
  value.to_s unless value.nil?
end

#load(value) ⇒ Object 



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# File 'lib/dm-types/uuid.rb', line 60

def load(value)
  if primitive?(value)
    value
  elsif !value.nil?
    UUIDTools::UUID.parse(value)
  end
end

#primitive?(value) ⇒ Boolean

We need to override this method otherwise typecast_to_primitive won’t be called. In the future we will set primitive to UUIDTools::UUID but this can happen only when adapters can handle it

Returns:

  • (Boolean) 


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# File 'lib/dm-types/uuid.rb', line 48

def primitive?(value)
  value.kind_of?(UUIDTools::UUID)
end

#typecast_to_primitive(value) ⇒ Object 



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# File 'lib/dm-types/uuid.rb', line 68

def typecast_to_primitive(value)
  load(value)
end

#valid?(value, negated = false) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dm-types/uuid.rb', line 52

def valid?(value, negated = false)
  super || dump(value).kind_of?(::String)
end