Module Sequel::Plugins::IdentityMap::ClassMethods
In: lib/sequel/plugins/identity_map.rb

Methods

Public Instance methods

Returns the current thread-local identity map. Should be a hash if there is an active identity map, and nil otherwise.

[Source]

    # File lib/sequel/plugins/identity_map.rb, line 41
41:         def identity_map
42:           Thread.current[:sequel_identity_map]
43:         end

The identity map key for an object of the current class with the given pk. May not always be correct for a class which uses STI.

[Source]

    # File lib/sequel/plugins/identity_map.rb, line 47
47:         def identity_map_key(pk)
48:           "#{self}:#{pk ? Array(pk).join(',') : "nil:#{rand}"}"
49:         end

If the identity map is in use, check it for a current copy of the object. If a copy does not exist, create a new object and add it to the identity map. If a copy exists, add any values in the given row that aren‘t currently in the object to the object‘s values. This allows you to only request certain fields in an initial query, make modifications to some of those fields and request other, potentially overlapping fields in a new query, and not have the second query override fields you modified.

[Source]

    # File lib/sequel/plugins/identity_map.rb, line 58
58:         def load(row)
59:           return super unless idm = identity_map
60:           if o = idm[identity_map_key(Array(primary_key).map{|x| row[x]})]
61:             o.merge_db_update(row)
62:           else
63:             o = super
64:             idm[identity_map_key(o.pk)] = o
65:           end
66:           o
67:         end

Take a block and inside that block use an identity map to ensure a 1-1 correspondence of objects to the database row they represent.

[Source]

    # File lib/sequel/plugins/identity_map.rb, line 71
71:         def with_identity_map
72:           return yield if identity_map
73:           begin
74:             self.identity_map = {}
75:             yield
76:           ensure
77:             self.identity_map = nil
78:           end
79:         end

[Validate]