Class: Sequel::Model::Associations::EagerGraphLoader
- Defined in:
- lib/sequel/model/associations.rb
Overview
This class is the internal implementation of eager_graph. It is responsible for taking an array of plain hashes and returning an array of model objects with all eager_graphed associations already set in the association cache.
Instance Attribute Summary collapse
-
#after_load_map ⇒ Object
readonly
Hash with table alias symbol keys and after_load hook values.
-
#alias_map ⇒ Object
readonly
Hash with table alias symbol keys and association name values.
-
#column_maps ⇒ Object
readonly
Hash with table alias symbol keys and subhash values mapping column_alias symbols to the symbol of the real name of the column.
-
#dependency_map ⇒ Object
readonly
Recursive hash with table alias symbol keys mapping to hashes with dependent table alias symbol keys.
-
#limit_map ⇒ Object
readonly
Hash with table alias symbol keys and [limit, offset] values.
-
#master ⇒ Object
readonly
Hash with table alias symbol keys and callable values used to create model instances The table alias symbol for the primary model.
-
#primary_keys ⇒ Object
readonly
Hash with table alias symbol keys and primary key symbol values (or arrays of primary key symbols for composite key tables).
-
#reciprocal_map ⇒ Object
readonly
Hash with table alias symbol keys and reciprocal association symbol values, used for setting reciprocals for one_to_many associations.
-
#records_map ⇒ Object
readonly
Hash with table alias symbol keys and subhash values mapping primary key symbols (or array of symbols) to model instances.
-
#reflection_map ⇒ Object
readonly
Hash with table alias symbol keys and AssociationReflection values.
-
#row_procs ⇒ Object
readonly
Hash with table alias symbol keys and callable values used to create model instances.
-
#type_map ⇒ Object
readonly
Hash with table alias symbol keys and true/false values, where true means the association represented by the table alias uses an array of values instead of a single value (i.e. true => *_many, false => *_to_one).
Instance Method Summary collapse
-
#initialize(dataset) ⇒ EagerGraphLoader
constructor
Initialize all of the data structures used during loading.
-
#load(hashes) ⇒ Object
Return an array of primary model instances with the associations cache prepopulated for all model objects (both primary and associated).
Constructor Details
#initialize(dataset) ⇒ EagerGraphLoader
Initialize all of the data structures used during loading.
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# File 'lib/sequel/model/associations.rb', line 2128 def initialize(dataset) opts = dataset.opts eager_graph = opts[:eager_graph] @master = eager_graph[:master] requirements = eager_graph[:requirements] reflection_map = @reflection_map = eager_graph[:reflections] reciprocal_map = @reciprocal_map = eager_graph[:reciprocals] @unique = eager_graph[:cartesian_product_number] > 1 alias_map = @alias_map = {} type_map = @type_map = {} after_load_map = @after_load_map = {} limit_map = @limit_map = {} reflection_map.each do |k, v| alias_map[k] = v[:name] type_map[k] = v.returns_array? after_load_map[k] = v[:after_load] unless v[:after_load].empty? limit_map[k] = v.limit_and_offset if v[:limit] end # Make dependency map hash out of requirements array for each association. # This builds a tree of dependencies that will be used for recursion # to ensure that all parts of the object graph are loaded into the # appropriate subordinate association. @dependency_map = {} # Sort the associations by requirements length, so that # requirements are added to the dependency hash before their # dependencies. requirements.sort_by{|a| a[1].length}.each do |ta, deps| if deps.empty? dependency_map[ta] = {} else deps = deps.dup hash = dependency_map[deps.shift] deps.each do |dep| hash = hash[dep] end hash[ta] = {} end end # This mapping is used to make sure that duplicate entries in the # result set are mapped to a single record. For example, using a # single one_to_many association with 10 associated records, # the main object column values appear in the object graph 10 times. # We map by primary key, if available, or by the object's entire values, # if not. The mapping must be per table, so create sub maps for each table # alias. records_map = {@master=>{}} alias_map.keys.each{|ta| records_map[ta] = {}} @records_map = records_map datasets = opts[:graph][:table_aliases].to_a.reject{|ta,ds| ds.nil?} column_aliases = opts[:graph_aliases] || opts[:graph][:column_aliases] primary_keys = {} column_maps = {} models = {} row_procs = {} datasets.each do |ta, ds| models[ta] = ds.model primary_keys[ta] = [] column_maps[ta] = {} row_procs[ta] = ds.row_proc end column_aliases.each do |col_alias, tc| ta, column = tc column_maps[ta][col_alias] = column end column_maps.each do |ta, h| pk = models[ta].primary_key if pk.is_a?(Array) primary_keys[ta] = [] h.select{|ca, c| primary_keys[ta] << ca if pk.include?(c)} else h.select{|ca, c| primary_keys[ta] = ca if pk == c} end end @column_maps = column_maps @primary_keys = primary_keys @row_procs = row_procs # For performance, create two special maps for the master table, # so you can skip a hash lookup. @master_column_map = column_maps[master] @master_primary_keys = primary_keys[master] # Add a special hash mapping table alias symbols to 5 element arrays that just # contain the data in other data structures for that table alias. This is # used for performance, to get all values in one hash lookup instead of # separate hash lookups for each data structure. ta_map = {} alias_map.keys.each do |ta| ta_map[ta] = [records_map[ta], row_procs[ta], alias_map[ta], type_map[ta], reciprocal_map[ta]] end @ta_map = ta_map end |
Instance Attribute Details
#after_load_map ⇒ Object (readonly)
Hash with table alias symbol keys and after_load hook values
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# File 'lib/sequel/model/associations.rb', line 2085 def after_load_map @after_load_map end |
#alias_map ⇒ Object (readonly)
Hash with table alias symbol keys and association name values
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# File 'lib/sequel/model/associations.rb', line 2088 def alias_map @alias_map end |
#column_maps ⇒ Object (readonly)
Hash with table alias symbol keys and subhash values mapping column_alias symbols to the symbol of the real name of the column
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# File 'lib/sequel/model/associations.rb', line 2092 def column_maps @column_maps end |
#dependency_map ⇒ Object (readonly)
Recursive hash with table alias symbol keys mapping to hashes with dependent table alias symbol keys.
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# File 'lib/sequel/model/associations.rb', line 2095 def dependency_map @dependency_map end |
#limit_map ⇒ Object (readonly)
Hash with table alias symbol keys and [limit, offset] values
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# File 'lib/sequel/model/associations.rb', line 2098 def limit_map @limit_map end |
#master ⇒ Object (readonly)
Hash with table alias symbol keys and callable values used to create model instances The table alias symbol for the primary model
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# File 'lib/sequel/model/associations.rb', line 2102 def master @master end |
#primary_keys ⇒ Object (readonly)
Hash with table alias symbol keys and primary key symbol values (or arrays of primary key symbols for composite key tables)
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# File 'lib/sequel/model/associations.rb', line 2106 def primary_keys @primary_keys end |
#reciprocal_map ⇒ Object (readonly)
Hash with table alias symbol keys and reciprocal association symbol values, used for setting reciprocals for one_to_many associations.
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# File 'lib/sequel/model/associations.rb', line 2110 def reciprocal_map @reciprocal_map end |
#records_map ⇒ Object (readonly)
Hash with table alias symbol keys and subhash values mapping primary key symbols (or array of symbols) to model instances. Used so that only a single model instance is created for each object.
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# File 'lib/sequel/model/associations.rb', line 2114 def records_map @records_map end |
#reflection_map ⇒ Object (readonly)
Hash with table alias symbol keys and AssociationReflection values
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# File 'lib/sequel/model/associations.rb', line 2117 def reflection_map @reflection_map end |
#row_procs ⇒ Object (readonly)
Hash with table alias symbol keys and callable values used to create model instances
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# File 'lib/sequel/model/associations.rb', line 2120 def row_procs @row_procs end |
#type_map ⇒ Object (readonly)
Hash with table alias symbol keys and true/false values, where true means the association represented by the table alias uses an array of values instead of a single value (i.e. true => *_many, false => *_to_one).
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# File 'lib/sequel/model/associations.rb', line 2125 def type_map @type_map end |
Instance Method Details
#load(hashes) ⇒ Object
Return an array of primary model instances with the associations cache prepopulated for all model objects (both primary and associated).
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# File 'lib/sequel/model/associations.rb', line 2227 def load(hashes) master = master() # Assign to local variables for speed increase rp = row_procs[master] rm = records_map[master] dm = dependency_map # This will hold the final record set that we will be replacing the object graph with. records = [] hashes.each do |h| unless key = master_pk(h) key = hkey(master_hfor(h)) end unless primary_record = rm[key] primary_record = rm[key] = rp.call(master_hfor(h)) # Only add it to the list of records to return if it is a new record records.push(primary_record) end # Build all associations for the current object and it's dependencies _load(dm, primary_record, h) end # Remove duplicate records from all associations if this graph could possibly be a cartesian product # Run after_load procs if there are any post_process(records, dm) if @unique || !after_load_map.empty? || !limit_map.empty? records end |