Class: ActiveFacts::Metamodel::EntityType
- Inherits:
-
DomainObjectType
- Object
- ObjectType
- DomainObjectType
- ActiveFacts::Metamodel::EntityType
- Defined in:
- lib/activefacts/persistence/columns.rb,
lib/activefacts/persistence/index.rb,
lib/activefacts/persistence/tables.rb,
lib/activefacts/vocabulary/metamodel.rb,
lib/activefacts/persistence/reference.rb,
lib/activefacts/vocabulary/extensions.rb,
lib/activefacts/generate/transform/surrogate.rb
Overview
The EntityType class is defined in the metamodel; full documentation is not generated. This section shows the features relevant to relational Persistence.
Instance Attribute Summary
Attributes inherited from ObjectType
#injected_surrogate_role, #tentative
Instance Method Summary collapse
-
#absorbed_via ⇒ Object
A Reference from an entity type that fully absorbs this one.
-
#absorbed_via=(r) ⇒ Object
:nodoc:.
-
#all_columns(excluded_supertypes) ⇒ Object
When absorbing this EntityType, what columns must be absorbed? This must be a fresh copy, because the columns will have References prepended.
- #all_supertype_inheritance ⇒ Object
- #assimilation ⇒ Object
-
#create_implicit_fact_types ⇒ Object
This entity type has just objectified a fact type.
- #identification_is_inherited ⇒ Object
-
#identifier_columns ⇒ Object
The identifier_columns for an EntityType are the columns that result from the identifying roles.
- #identifying_refs_from ⇒ Object
-
#identifying_supertype ⇒ Object
A subtype does not have a identifying_supertype if it defines its own identifier.
- #inject_surrogate ⇒ Object
-
#is_auto_assigned ⇒ Object
:nodoc:.
-
#is_table ⇒ Object
Returns true if this EntityType is a table.
- #needs_surrogate ⇒ Object
-
#populate_references ⇒ Object
:nodoc:.
- #preferred_identifier ⇒ Object
-
#reference_columns(excluded_supertypes) ⇒ Object
When creating a foreign key to this EntityType, what columns must we include (the identifier columns)? This must be a fresh copy, because the columns will have References prepended.
- #self_index ⇒ Object
-
#subtypes ⇒ Object
An array of all direct subtypes:.
- #subtypes_transitive ⇒ Object
-
#supertypes ⇒ Object
An array all direct supertypes.
-
#supertypes_transitive ⇒ Object
An array of self followed by all supertypes in order:.
Methods inherited from ObjectType
#add_surrogate, #all_absorbed_foreign_key_reference_path, #clear_indices, #clear_references, #columns, #definitely_not_table, #definitely_table, #foreign_keys, #foreign_keys_to, #has_references, #indices, #populate_columns, #populate_indices, #populate_reference, #probably_not_table, #probably_table, #rails_class_name, #rails_name, #rails_singular_name, #references_from, #references_to, #show_tabular
Instance Method Details
#absorbed_via ⇒ Object
A Reference from an entity type that fully absorbs this one
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# File 'lib/activefacts/persistence/tables.rb', line 60 def absorbed_via; @absorbed_via; end |
#absorbed_via=(r) ⇒ Object
:nodoc:
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# File 'lib/activefacts/persistence/tables.rb', line 61 def absorbed_via=(r) #:nodoc: @absorbed_via = r end |
#all_columns(excluded_supertypes) ⇒ Object
When absorbing this EntityType, what columns must be absorbed? This must be a fresh copy, because the columns will have References prepended.
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# File 'lib/activefacts/persistence/columns.rb', line 346 def all_columns(excluded_supertypes) #:nodoc: debug :columns, "All Columns for #{name}" do columns = [] sups = supertypes pi_roles = preferred_identifier.role_sequence.all_role_ref.map{|rr| rr.role} references_from.sort_by do |ref| # Put supertypes first, in order, then PI roles, non-subtype references by name, then subtypes by name: next [0, p] if p = sups.index(ref.to) if !ref.fact_type.is_a?(ActiveFacts::Metamodel::TypeInheritance) next [1, p] if p = pi_roles.index(ref.to_role) next [2, ref.to_names] end [3, ref.to_names] end.each do |ref| debug :columns, "Columns absorbed via #{ref}" do if (ref.role_type == :supertype) if excluded_supertypes[ref.to] debug :columns, "Exclude #{ref.to.name}, we already inherited it" next end next if (ref.to.absorbed_via != ref) excluded_supertypes[ref.to] = true columns += ref.columns(excluded_supertypes) else columns += ref.columns({}) end end end columns end end |
#all_supertype_inheritance ⇒ Object
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# File 'lib/activefacts/vocabulary/extensions.rb', line 445 def all_supertype_inheritance all_type_inheritance_as_subtype.sort_by{|ti| [ti.provides_identification ? 0 : 1, ti.supertype.name] } end |
#assimilation ⇒ Object
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# File 'lib/activefacts/vocabulary/extensions.rb', line 273 def assimilation if rr = identification_is_inherited rr.role.fact_type.assimilation else nil end end |
#create_implicit_fact_types ⇒ Object
This entity type has just objectified a fact type. Create the necessary ImplicitFactTypes with phantom roles
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# File 'lib/activefacts/vocabulary/extensions.rb', line 479 def create_implicit_fact_types fact_type.all_role.map do |role| next if role.link_fact_type # Already exists link_fact_type = @constellation.LinkFactType(:new, :implying_role => role) phantom_role = @constellation.Role(link_fact_type, 0, :object_type => self, :concept => :new) # We could create a copy of the visible external role here, but there's no need yet... # Nor is there a need for a presence constraint, readings, etc. link_fact_type end end |
#identification_is_inherited ⇒ Object
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# File 'lib/activefacts/vocabulary/extensions.rb', line 268 def identification_is_inherited preferred_identifier and preferred_identifier.role_sequence.all_role_ref.detect{|rr| rr.role.fact_type.is_a?(ActiveFacts::Metamodel::TypeInheritance) } end |
#identifier_columns ⇒ Object
The identifier_columns for an EntityType are the columns that result from the identifying roles
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# File 'lib/activefacts/persistence/columns.rb', line 299 def identifier_columns debug :columns, "Identifier Columns for #{name}" do if absorbed_via and # If this is a subtype that has its own identification, use that. (all_type_inheritance_as_subtype.size == 0 || all_type_inheritance_as_subtype.detect{|ti| ti.provides_identification }) return absorbed_via.from.identifier_columns end preferred_identifier.role_sequence.all_role_ref.map do |role_ref| ref = references_from.detect {|ref| ref.to_role == role_ref.role} columns.select{|column| column.references[0] == ref} end.flatten end end |
#identifying_refs_from ⇒ Object
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# File 'lib/activefacts/generate/transform/surrogate.rb', line 80 def pi = preferred_identifier rrs = pi.role_sequence.all_role_ref # REVISIT: This is actually a ref to us, not from # if absorbed_via # return [absorbed_via] # end rrs.map do |rr| r = references_from.detect{|ref| rr.role == ref.to_role } raise "failed to find #{name} identifying reference for #{rr.role.object_type.name} in #{references_from.inspect}" unless r r end end |
#identifying_supertype ⇒ Object
A subtype does not have a identifying_supertype if it defines its own identifier
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# File 'lib/activefacts/vocabulary/extensions.rb', line 466 def debug "Looking for identifying_supertype of #{name}" all_type_inheritance_as_subtype.detect{|ti| debug "considering supertype #{ti.supertype.name}" next unless ti.provides_identification debug "found identifying supertype of #{name}, it's #{ti.supertype.name}" return ti.supertype } debug "Failed to find identifying supertype of #{name}" return nil end |
#inject_surrogate ⇒ Object
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# File 'lib/activefacts/generate/transform/surrogate.rb', line 159 def inject_surrogate debug :transform_surrogate, "Injecting a surrogate key into #{self.name}" # Disable the preferred identifier: pi = preferred_identifier debug :transform_surrogate, "pi for #{name} was '#{pi.describe}'" pi.is_preferred_identifier = false @preferred_identifier = nil # Kill the cache add_surrogate debug :transform_surrogate, "pi for #{name} is now '#{preferred_identifier.describe}'" end |
#is_auto_assigned ⇒ Object
:nodoc:
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# File 'lib/activefacts/persistence/tables.rb', line 65 def is_auto_assigned #:nodoc: false end |
#is_table ⇒ Object
Returns true if this EntityType is a table
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# File 'lib/activefacts/persistence/tables.rb', line 70 def is_table return @is_table if @is_table != nil # We already make a guess or decision @tentative = false # Always a table if marked so if is_independent debug :absorption, "EntityType #{name} is declared independent" return @is_table = true end # Always a table if nowhere else to go, and has no one-to-ones that might flip: if references_to.empty? and !references_from.detect{|ref| ref.role_type == :one_one } debug :absorption, "EntityType #{name} is presumed independent as it has nowhere to go" return @is_table = true end # Subtypes may be partitioned or separate, in which case they're definitely tables. # Otherwise, if their identification is inherited from a supertype, they're definitely absorbed. # If theey have separate identification, it might absorb them. if (!supertypes.empty?) as_ti = all_supertype_inheritance.detect{|ti| ti.assimilation} @is_table = as_ti != nil if @is_table debug :absorption, "EntityType #{name} is #{as_ti.assimilation} from supertype #{as_ti.supertype}" else = preferred_identifier.role_sequence.all_role_ref.to_a[0].role.fact_type if .is_a?(TypeInheritance) debug :absorption, "EntityType #{name} is absorbed into supertype #{supertypes[0].name}" @is_table = false else # Possibly absorbed, we'll have to see how that pans out @tentative = true end end return @is_table end # If the preferred_identifier includes an auto_assigned ValueType # and this object is absorbed in more than one place, we need a table # to manage the auto-assignment. if references_to.size > 1 and preferred_identifier.role_sequence.all_role_ref.detect {|rr| next false unless rr.role.object_type.is_a? ValueType rr.role.object_type.is_auto_assigned } debug :absorption, "#{name} has an auto-assigned counter in its ID, so must be a table" @tentative = false return @is_table = true end @tentative = true @is_table = true end |
#needs_surrogate ⇒ Object
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# File 'lib/activefacts/generate/transform/surrogate.rb', line 96 def needs_surrogate # A recursive proc to replace any reference to an Entity Type by its identifying references: debug :transform_surrogate_expansion, "Expanding key for #{name}" = proc do |object| if ref = object.absorbed_via # This shouldn't be necessary, but see the absorbed_via comment above. absorbed_into = ref.from debug :transform_surrogate_expansion, "recursing to handle absorption of #{object.name} into #{absorbed_into.name}" [.call(absorbed_into)] else irf = object. debug :transform_surrogate_expansion, "Iterating for #{object.name} over #{irf.inspect}" do irf.each_with_index do |ref, i| next if ref.is_unary next if ref.to_role.object_type.kind_of?(ActiveFacts::Metamodel::ValueType) recurse_to = ref.to_role.object_type debug :transform_surrogate_expansion, "#{i}: recursing to expand #{recurse_to.name} key in #{ref}" do irf[i] = .call(recurse_to) end end end irf end end irf = .call(self) debug :transform_surrogate, "Does #{name} need a surrogate? it's identified by #{irf.inspect}" do pk_fks = .map do |ref| ref.to && ref.to.is_table ? ref.to : nil end irf.flatten! # Multi-part identifiers are only allowed if each part is a foreign key (i.e. it's a join table) and the object is not the target of a foreign key: if irf.size >= 2 if pk_fks.include?(nil) debug :transform_surrogate, "#{self.name} needs a surrogate because its multi-part key contains a non-table" return true elsif references_to.size != 0 debug :transform_surrogate, "#{self.name} is a join table between #{pk_fks.map(&:name).inspect} but is also an FK target" return true else debug :transform_surrogate, "#{self.name} is a join table between #{pk_fks.map(&:name).inspect}" return false end return true end # Single-part key. It must be an Auto Counter, or we will add a surrogate = irf[0].to if .needs_surrogate debug :transform_surrogate, "#{self.name} needs a surrogate because #{irf[0].to.name} is not an AutoCounter, but #{.supertypes_transitive.map(&:name).inspect}" return true end false end end |
#populate_references ⇒ Object
:nodoc:
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# File 'lib/activefacts/persistence/reference.rb', line 371 def populate_references #:nodoc: if fact_type && fact_type.all_role.size > 1 # NOT: fact_type.all_role.each do |role| # Place roles in the preferred order instead: fact_type.preferred_reading.role_sequence.all_role_ref.map(&:role).each do |role| populate_reference role # Objectified fact role, handled specially end end super end |
#preferred_identifier ⇒ Object
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# File 'lib/activefacts/vocabulary/extensions.rb', line 281 def preferred_identifier return @preferred_identifier if @preferred_identifier if fact_type # When compiling a fact instance, the delayed creation of a preferred identifier might be necessary if c = fact_type.check_and_add_spanning_uniqueness_constraint fact_type.check_and_add_spanning_uniqueness_constraint = nil c.call end # For a nested fact type, the PI is a unique constraint over N or N-1 roles fact_roles = Array(fact_type.all_role) debug :pi, "Looking for PI on nested fact type #{name}" do pi = catch :pi do fact_roles[0,2].each{|r| # Try the first two roles of the fact type, that's enough r.all_role_ref.map{|rr| # All role sequences that reference this role role_sequence = rr.role_sequence # The role sequence is only interesting if it cover only this fact's roles # or roles of the objectification next if role_sequence.all_role_ref.size < fact_roles.size-1 # Not enough roles next if role_sequence.all_role_ref.size > fact_roles.size # Too many roles next if role_sequence.all_role_ref.detect do |rsr| if (of = rsr.role.fact_type) != fact_type case of.all_role.size when 1 # A unary FT must be played by the objectification of this fact type next rsr.role.object_type != fact_type.entity_type when 2 # A binary FT must have the objectification of this FT as the other player other_role = (of.all_role-[rsr.role])[0] next other_role.object_type != fact_type.entity_type else next true # A role in a ternary (or higher) cannot be usd in our identifier end end rsr.role.fact_type != fact_type end # This role sequence is a candidate pc = role_sequence.all_presence_constraint.detect{|c| c.max_frequency == 1 && c.is_preferred_identifier } throw :pi, pc if pc } } throw :pi, nil end debug :pi, "Got PI #{pi.name||pi.object_id} for nested #{name}" if pi debug :pi, "Looking for PI on entity that nests this fact" unless pi raise "Oops, pi for nested fact is #{pi.class}" unless !pi || pi.is_a?(ActiveFacts::Metamodel::PresenceConstraint) return @preferred_identifier = pi if pi end end debug :pi, "Looking for PI for ordinary entity #{name} with #{all_role.size} roles:" do debug :pi, "Roles are in fact types #{all_role.map{|r| r.fact_type.describe(r)}*", "}" pi = catch :pi do all_supertypes = supertypes_transitive debug :pi, "PI roles must be played by one of #{all_supertypes.map(&:name)*", "}" if all_supertypes.size > 1 all_role.each{|role| next unless role.unique || fact_type ftroles = Array(role.fact_type.all_role) # Skip roles in ternary and higher fact types, they're objectified, and in unaries, they can't identify us. next if ftroles.size != 2 debug :pi, "Considering role in #{role.fact_type.describe(role)}" # Find the related role which must be included in any PI: # Note this works with unary fact types: pi_role = ftroles[ftroles[0] != role ? 0 : -1] next if ftroles.size == 2 && pi_role.object_type == self debug :pi, " Considering #{pi_role.object_type.name} as a PI role" # If this is an identifying role, the PI is a PC whose role_sequence spans the role. # Walk through all role_sequences that span this role, and test each: pi_role.all_role_ref.each{|rr| role_sequence = rr.role_sequence # A role sequence that includes a possible role debug :pi, " Considering role sequence #{role_sequence.describe}" # All roles in this role_sequence must be in fact types which # (apart from that role) only have roles played by the original # entity type or a supertype. #debug :pi, " All supertypes #{all_supertypes.map{|st| "#{st.object_id}=>#{st.name}"}*", "}" if role_sequence.all_role_ref.detect{|rsr| fact_type = rsr.role.fact_type debug :pi, " Role Sequence touches #{fact_type.describe(pi_role)}" fact_type_roles = fact_type.all_role debug :pi, " residual is #{fact_type_roles.map{|r| r.object_type.name}.inspect} minus #{rsr.role.object_type.name}" residual_roles = fact_type_roles-[rsr.role] residual_roles.detect{|rfr| debug :pi, " Checking residual role #{rfr.object_type.object_id}=>#{rfr.object_type.name}" # This next line looks right, but breaks things. Find out what and why: # !rfr.unique or !all_supertypes.include?(rfr.object_type) } } debug :pi, " Discounting this role_sequence because it includes alien roles" next end # Any presence constraint over this role sequence is a candidate rr.role_sequence.all_presence_constraint.detect{|pc| # Found it! if pc.is_preferred_identifier debug :pi, "found PI #{pc.name||pc.object_id}, is_preferred_identifier=#{pc.is_preferred_identifier.inspect} over #{pc.role_sequence.describe}" throw :pi, pc end } } } throw :pi, nil end raise "Oops, pi for entity is #{pi.class}" if pi && !pi.is_a?(ActiveFacts::Metamodel::PresenceConstraint) debug :pi, "Got PI #{pi.name||pi.object_id} for #{name}" if pi if !pi if (supertype = ) # This shouldn't happen now, as an identifying supertype is connected by a fact type # that has a uniqueness constraint marked as the preferred identifier. #debug :pi, "PI not found for #{name}, looking in supertype #{supertype.name}" #pi = supertype.preferred_identifier #return nil elsif fact_type possible_pi = nil fact_type.all_role.each{|role| role.all_role_ref.each{|role_ref| # Discount role sequences that contain roles not in this fact type: next if role_ref.role_sequence.all_role_ref.detect{|rr| rr.role.fact_type != fact_type } role_ref.role_sequence.all_presence_constraint.each{|pc| next unless pc.max_frequency == 1 possible_pi = pc next unless pc.is_preferred_identifier pi = pc break } break if pi } break if pi } if !pi && possible_pi debug :pi, "Using existing PC as PI for #{name}" pi = possible_pi end else debug :pi, "No PI found for #{name}" end end raise "No PI found for #{name}" unless pi @preferred_identifier = pi end end |
#reference_columns(excluded_supertypes) ⇒ Object
When creating a foreign key to this EntityType, what columns must we include (the identifier columns)? This must be a fresh copy, because the columns will have References prepended
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# File 'lib/activefacts/persistence/columns.rb', line 318 def reference_columns(excluded_supertypes) #:nodoc: debug :columns, "Reference Columns for #{name}" do if absorbed_via and # If this is not a subtype, or is a subtype that has its own identification, use the id. (all_type_inheritance_as_subtype.size == 0 || all_type_inheritance_as_subtype.detect{|ti| ti.provides_identification }) rc = absorbed_via.from.reference_columns(excluded_supertypes) # The absorbed_via reference gets skipped here, ans also in object_type.rb debug :columns, "Skipping #{absorbed_via}" #rc.each{|col| col.prepend(absorbed_via)} return rc end # REVISIT: Should have built preferred_identifier_references preferred_identifier.role_sequence.all_role_ref.map do |role_ref| # REVISIT: Should index references by to_role: ref = references_from.detect {|ref| ref.to_role == role_ref.role} raise "reference for role #{role_ref.describe} not found on #{name} in #{references_from.size} references:\n\t#{references_from.map(&:to_s)*"\n\t"}" unless ref ref.columns({}) end.flatten end end |
#self_index ⇒ Object
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# File 'lib/activefacts/persistence/index.rb', line 87 def self_index nil end |
#subtypes ⇒ Object
An array of all direct subtypes:
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# File 'lib/activefacts/vocabulary/extensions.rb', line 436 def subtypes # REVISIT: There's no sorting here. Should there be? all_type_inheritance_as_supertype.map{|ti| ti.subtype } end |
#subtypes_transitive ⇒ Object
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# File 'lib/activefacts/vocabulary/extensions.rb', line 441 def subtypes_transitive [self] + subtypes.map{|st| st.subtypes_transitive}.flatten.uniq end |
#supertypes ⇒ Object
An array all direct supertypes
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# File 'lib/activefacts/vocabulary/extensions.rb', line 452 def supertypes all_supertype_inheritance.map{|ti| ti.supertype } end |
#supertypes_transitive ⇒ Object
An array of self followed by all supertypes in order:
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# File 'lib/activefacts/vocabulary/extensions.rb', line 459 def supertypes_transitive ([self] + all_type_inheritance_as_subtype.map{|ti| ti.supertype.supertypes_transitive }).flatten.uniq end |