Each kind of association adds a number of instance methods to the model class which are specialized according to the association type and optional parameters given in the definition. Example:
class Project < Sequel::Model many_to_one :portfolio # or: one_to_one :portfolio one_to_many :milestones # or: many_to_many :milestones end
The project class now has the following instance methods:
portfolio | Returns the associated portfolio. |
portfolio=(obj) | Sets the associated portfolio to the object, but the change is not persisted until you save the record (for many_to_one associations). |
portfolio_dataset | Returns a dataset that would return the associated portfolio, only useful in fairly specific circumstances. |
milestones | Returns an array of associated milestones |
add_milestone(obj) | Associates the passed milestone with this object. |
remove_milestone(obj) | Removes the association with the passed milestone. |
remove_all_milestones | Removes associations with all associated milestones. |
milestones_dataset | Returns a dataset that would return the associated milestones, allowing for further filtering/limiting/etc. |
If you want to override the behavior of the add_/remove_/remove_all_/ methods or the association setter method, there are private instance methods created that are prepended with an underscore (e.g. _add_milestone or _portfolio=). The private instance methods can be easily overridden, but you shouldn’t override the public instance methods without calling super, as they deal with callbacks and caching.
By default the classes for the associations are inferred from the association name, so for example the Project#portfolio will return an instance of Portfolio, and Project#milestones will return an array of Milestone instances. You can use the :class option to change which class is used.
Association definitions are also reflected by the class, e.g.:
Project.associations => [:portfolio, :milestones] Project.association_reflection(:portfolio) => {:type => :many_to_one, :name => :portfolio, ...}
Associations should not have the same names as any of the columns in the model’s current table they reference. If you are dealing with an existing schema that has a column named status, you can’t name the association status, you’d have to name it foo_status or something else. If you give an association the same name as a column, you will probably end up with an association that doesn’t work, or a SystemStackError.
For a more in depth general overview, as well as a reference guide, see the Association Basics guide. For examples of advanced usage, see the Advanced Associations guide.
Array of all association reflections for this model class
# File lib/sequel/model/associations.rb, line 672 672: def all_association_reflections 673: association_reflections.values 674: end
Given an association reflection and a dataset, apply the :select, :conditions, :order, :eager, :distinct, and :eager_block association options to the given dataset and return the dataset or a modified copy of it.
# File lib/sequel/model/associations.rb, line 680 680: def apply_association_dataset_opts(opts, ds) 681: ds = ds.select(*opts.select) if opts.select 682: if c = opts[:conditions] 683: ds = (c.is_a?(Array) && !Sequel.condition_specifier?(c)) ? ds.filter(*c) : ds.filter(c) 684: end 685: ds = ds.order(*opts[:order]) if opts[:order] 686: ds = ds.eager(opts[:eager]) if opts[:eager] 687: ds = ds.distinct if opts[:distinct] 688: ds = opts[:eager_block].call(ds) if opts[:eager_block] 689: ds 690: end
Associates a related model with the current model. The following types are supported:
:many_to_one | Foreign key in current model’s table points to associated model’s primary key. Each associated model object can be associated with more than one current model objects. Each current model object can be associated with only one associated model object. |
:one_to_many | Foreign key in associated model’s table points to this model’s primary key. Each current model object can be associated with more than one associated model objects. Each associated model object can be associated with only one current model object. |
:one_to_one | Similar to one_to_many in terms of foreign keys, but only one object is associated to the current object through the association. The methods created are similar to many_to_one, except that the one_to_one setter method saves the passed object. |
:many_to_many | A join table is used that has a foreign key that points to this model’s primary key and a foreign key that points to the associated model’s primary key. Each current model object can be associated with many associated model objects, and each associated model object can be associated with many current model objects. |
The following options can be supplied:
:after_add | Symbol, Proc, or array of both/either specifying a callback to call after a new item is added to the association. |
:after_load | Symbol, Proc, or array of both/either specifying a callback to call after the associated record(s) have been retrieved from the database. |
:after_remove | Symbol, Proc, or array of both/either specifying a callback to call after an item is removed from the association. |
:after_set | Symbol, Proc, or array of both/either specifying a callback to call after an item is set using the association setter method. |
:allow_eager | If set to false, you cannot load the association eagerly via eager or eager_graph |
:before_add | Symbol, Proc, or array of both/either specifying a callback to call before a new item is added to the association. |
:before_remove | Symbol, Proc, or array of both/either specifying a callback to call before an item is removed from the association. |
:before_set | Symbol, Proc, or array of both/either specifying a callback to call before an item is set using the association setter method. |
:cartesian_product_number | the number of joins completed by this association that could cause more than one row for each row in the current table (default: 0 for many_to_one and one_to_one associations, 1 for one_to_many and many_to_many associations). |
:class | The associated class or its name. If not given, uses the association’s name, which is camelized (and singularized unless the type is :many_to_one or :one_to_one) |
:clone | Merge the current options and block into the options and block used in defining the given association. Can be used to DRY up a bunch of similar associations that all share the same options such as :class and :key, while changing the order and block used. |
:conditions | The conditions to use to filter the association, can be any argument passed to filter. |
:dataset | A proc that is instance_evaled to get the base dataset to use for the _dataset method (before the other options are applied). |
:distinct | Use the DISTINCT clause when selecting associating object, both when lazy loading and eager loading via .eager (but not when using .eager_graph). |
:eager | The associations to eagerly load via eager when loading the associated object(s). |
:eager_block | If given, use the block instead of the default block when eagerly loading. To not use a block when eager loading (when one is used normally), set to nil. |
:eager_graph | The associations to eagerly load via eager_graph when loading the associated object(s). many_to_many associations with this option cannot be eagerly loaded via eager. |
:eager_grapher | A proc to use to implement eager loading via eager_graph, overriding the default. Takes one or three arguments. If three arguments, they are a dataset, an alias to use for the table to graph for this association, and the alias that was used for the current table (since you can cascade associations). If one argument, is passed a hash with keys :self, :table_alias, and :implicit_qualifier, corresponding to the three arguments, and an optional additional key :eager_block, a callback accepting one argument, the associated dataset. This is used to customize the association at query time. Should return a copy of the dataset with the association graphed into it. |
:eager_limit_strategy | Determines the strategy used for enforcing limits when eager loading associations via the eager method. For one_to_one associations, no strategy is used by default, and for *_many associations, the :ruby strategy is used by default, which still retrieves all records but slices the resulting array after the association is retrieved. You can pass a true value for this option to have Sequel pick what it thinks is the best choice for the database, or specify a specific symbol to manually select a strategy. one_to_one associations support :distinct_on, :window_function, and :correlated_subquery. *_many associations support :ruby, :window_function, and :correlated_subquery. |
:eager_loader | A proc to use to implement eager loading, overriding the default. Takes one or three arguments. If three arguments, the first should be a key hash (used solely to enhance performance), the second an array of records, and the third a hash of dependent associations. If one argument, is passed a hash with keys :key_hash, :rows, and :associations, corresponding to the three arguments, and an additional key :self, which is the dataset doing the eager loading. In the proc, the associated records should be queried from the database and the associations cache for each record should be populated. |
:eager_loader_key | A symbol for the key column to use to populate the key hash for the eager loader. |
:extend | A module or array of modules to extend the dataset with. |
:graph_alias_base | The base name to use for the table alias when eager graphing. Defaults to the name of the association. If the alias name has already been used in the query, Sequel will create a unique alias by appending a numeric suffix (e.g. alias_0, alias_1, …) until the alias is unique. |
:graph_block | The block to pass to join_table when eagerly loading the association via eager_graph. |
:graph_conditions | The additional conditions to use on the SQL join when eagerly loading the association via eager_graph. Should be a hash or an array of two element arrays. If not specified, the :conditions option is used if it is a hash or array of two element arrays. |
:graph_join_type | The type of SQL join to use when eagerly loading the association via eager_graph. Defaults to :left_outer. |
:graph_only_conditions | The conditions to use on the SQL join when eagerly loading the association via eager_graph, instead of the default conditions specified by the foreign/primary keys. This option causes the :graph_conditions option to be ignored. |
:graph_select | A column or array of columns to select from the associated table when eagerly loading the association via eager_graph. Defaults to all columns in the associated table. |
:limit | Limit the number of records to the provided value. Use an array with two elements for the value to specify a limit (first element) and an offset (second element). |
:methods_module | The module that methods the association creates will be placed into. Defaults to the module containing the model’s columns. |
:order | the column(s) by which to order the association dataset. Can be a singular column symbol or an array of column symbols. |
:order_eager_graph | Whether to add the association’s order to the graphed dataset’s order when graphing via eager_graph. Defaults to true, so set to false to disable. |
:read_only | Do not add a setter method (for many_to_one or one_to_one associations), or add_/remove_/remove_all_ methods (for one_to_many and many_to_many associations). |
:reciprocal | the symbol name of the reciprocal association, if it exists. By default, Sequel will try to determine it by looking at the associated model’s assocations for a association that matches the current association’s key(s). Set to nil to not use a reciprocal. |
:select | the columns to select. Defaults to the associated class’s table_name.* in a many_to_many association, which means it doesn’t include the attributes from the join table. If you want to include the join table attributes, you can use this option, but beware that the join table attributes can clash with attributes from the model table, so you should alias any attributes that have the same name in both the join table and the associated table. |
:validate | Set to false to not validate when implicitly saving any associated object. |
:key | foreign key in current model’s table that references associated model’s primary key, as a symbol. Defaults to :”#{name}_id”. Can use an array of symbols for a composite key association. |
:key_column | Similar to, and usually identical to, :key, but :key refers to the model method to call, where :key_column refers to the underlying column. Should only be used if the the model method differs from the foreign key column, in conjunction with defining a model alias method for the key column. |
:primary_key | column in the associated table that :key option references, as a symbol. Defaults to the primary key of the associated table. Can use an array of symbols for a composite key association. |
:primary_key_method | the method symbol or array of method symbols to call on the associated object to get the foreign key values. Defaults to :primary_key option. |
:qualify | Whether to use qualifier primary keys when loading the association. The default is true, so you must set to false to not qualify. Qualification rarely causes problems, but it’s necessary to disable in some cases, such as when you are doing a JOIN USING operation on the column on Oracle. |
:key | foreign key in associated model’s table that references current model’s primary key, as a symbol. Defaults to :”#{self.name.underscore}_id”. Can use an array of symbols for a composite key association. |
:key_method | the method symbol or array of method symbols to call on the associated object to get the foreign key values. Defaults to :key option. |
:primary_key | column in the current table that :key option references, as a symbol. Defaults to primary key of the current table. Can use an array of symbols for a composite key association. |
:primary_key_column | Similar to, and usually identical to, :primary_key, but :primary_key refers to the model method call, where :primary_key_column refers to the underlying column. Should only be used if the the model method differs from the primary key column, in conjunction with defining a model alias method for the primary key column. |
:graph_join_table_block | The block to pass to join_table for the join table when eagerly loading the association via eager_graph. |
:graph_join_table_conditions | The additional conditions to use on the SQL join for the join table when eagerly loading the association via eager_graph. Should be a hash or an array of two element arrays. |
:graph_join_table_join_type | The type of SQL join to use for the join table when eagerly loading the association via eager_graph. Defaults to the :graph_join_type option or :left_outer. |
:graph_join_table_only_conditions | The conditions to use on the SQL join for the join table when eagerly loading the association via eager_graph, instead of the default conditions specified by the foreign/primary keys. This option causes the :graph_join_table_conditions option to be ignored. |
:join_table | name of table that includes the foreign keys to both the current model and the associated model, as a symbol. Defaults to the name of current model and name of associated model, pluralized, underscored, sorted, and joined with ‘_’. |
:join_table_block | proc that can be used to modify the dataset used in the add/remove/remove_all methods. Should accept a dataset argument and return a modified dataset if present. |
:left_key | foreign key in join table that points to current model’s primary key, as a symbol. Defaults to :”#{self.name.underscore}_id”. Can use an array of symbols for a composite key association. |
:left_primary_key | column in current table that :left_key points to, as a symbol. Defaults to primary key of current table. Can use an array of symbols for a composite key association. |
:left_primary_key_column | Similar to, and usually identical to, :left_primary_key, but :left_primary_key refers to the model method to call, where :left_primary_key_column refers to the underlying column. Should only be used if the model method differs from the left primary key column, in conjunction with defining a model alias method for the left primary key column. |
:right_key | foreign key in join table that points to associated model’s primary key, as a symbol. Defaults to :”#{name.to_s.singularize}_id”. Can use an array of symbols for a composite key association. |
:right_primary_key | column in associated table that :right_key points to, as a symbol. Defaults to primary key of the associated table. Can use an array of symbols for a composite key association. |
:right_primary_key_method | the method symbol or array of method symbols to call on the associated object to get the foreign key values for the join table. Defaults to :right_primary_key option. |
:uniq | Adds a after_load callback that makes the array of objects unique. |
# File lib/sequel/model/associations.rb, line 888 888: def associate(type, name, opts = {}, &block) 889: raise(Error, 'one_to_many association type with :one_to_one option removed, used one_to_one association type') if opts[:one_to_one] && type == :one_to_many 890: raise(Error, 'invalid association type') unless assoc_class = ASSOCIATION_TYPES[type] 891: raise(Error, 'Model.associate name argument must be a symbol') unless Symbol === name 892: raise(Error, ':eager_loader option must have an arity of 1 or 3') if opts[:eager_loader] && ![1, 3].include?(opts[:eager_loader].arity) 893: raise(Error, ':eager_grapher option must have an arity of 1 or 3') if opts[:eager_grapher] && ![1, 3].include?(opts[:eager_grapher].arity) 894: 895: # dup early so we don't modify opts 896: orig_opts = opts.dup 897: orig_opts = association_reflection(opts[:clone])[:orig_opts].merge(orig_opts) if opts[:clone] 898: opts = orig_opts.merge(:type => type, :name => name, :cache=>{}, :model => self) 899: opts[:block] = block if block 900: opts = assoc_class.new.merge!(opts) 901: opts[:eager_block] = block unless opts.include?(:eager_block) 902: opts[:graph_join_type] ||= :left_outer 903: opts[:order_eager_graph] = true unless opts.include?(:order_eager_graph) 904: conds = opts[:conditions] 905: opts[:graph_alias_base] ||= name 906: opts[:graph_conditions] = conds if !opts.include?(:graph_conditions) and Sequel.condition_specifier?(conds) 907: opts[:graph_conditions] = opts.fetch(:graph_conditions, []).to_a 908: opts[:graph_select] = Array(opts[:graph_select]) if opts[:graph_select] 909: [:before_add, :before_remove, :after_add, :after_remove, :after_load, :before_set, :after_set, :extend].each do |cb_type| 910: opts[cb_type] = Array(opts[cb_type]) 911: end 912: late_binding_class_option(opts, opts.returns_array? ? singularize(name) : name) 913: 914: # Remove :class entry if it exists and is nil, to work with cached_fetch 915: opts.delete(:class) unless opts[:class] 916: 917: send(:"def_#{type}", opts) 918: 919: orig_opts.delete(:clone) 920: orig_opts.merge!(:class_name=>opts[:class_name], :class=>opts[:class], :block=>block) 921: opts[:orig_opts] = orig_opts 922: # don't add to association_reflections until we are sure there are no errors 923: association_reflections[name] = opts 924: end
The association reflection hash for the association of the given name.
# File lib/sequel/model/associations.rb, line 927 927: def association_reflection(name) 928: association_reflections[name] 929: end
Array of association name symbols
# File lib/sequel/model/associations.rb, line 932 932: def associations 933: association_reflections.keys 934: end
Modify and return eager loading dataset based on association options.
# File lib/sequel/model/associations.rb, line 937 937: def eager_loading_dataset(opts, ds, select, associations, eager_options={}) 938: ds = apply_association_dataset_opts(opts, ds) 939: ds = ds.select(*select) if select 940: if opts[:eager_graph] 941: raise(Error, "cannot eagerly load a #{opts[:type]} association that uses :eager_graph") if opts.eager_loading_use_associated_key? 942: ds = ds.eager_graph(opts[:eager_graph]) 943: end 944: ds = ds.eager(associations) unless Array(associations).empty? 945: ds = eager_options[:eager_block].call(ds) if eager_options[:eager_block] 946: if opts.eager_loading_use_associated_key? 947: ds = if opts[:uses_left_composite_keys] 948: ds.select_append(*opts.associated_key_alias.zip(opts.eager_loading_predicate_key).map{|a, k| SQL::AliasedExpression.new(k, a)}) 949: else 950: ds.select_append(SQL::AliasedExpression.new(opts.eager_loading_predicate_key, opts.associated_key_alias)) 951: end 952: end 953: ds 954: end
Copy the association reflections to the subclass
# File lib/sequel/model/associations.rb, line 957 957: def inherited(subclass) 958: super 959: subclass.instance_variable_set(:@association_reflections, association_reflections.dup) 960: subclass.default_eager_limit_strategy = default_eager_limit_strategy 961: end
Shortcut for adding a many_to_many association, see #
# File lib/sequel/model/associations.rb, line 964 964: def many_to_many(name, opts={}, &block) 965: associate(:many_to_many, name, opts, &block) 966: end
Shortcut for adding a many_to_one association, see #
# File lib/sequel/model/associations.rb, line 969 969: def many_to_one(name, opts={}, &block) 970: associate(:many_to_one, name, opts, &block) 971: end
Shortcut for adding a one_to_many association, see #
# File lib/sequel/model/associations.rb, line 974 974: def one_to_many(name, opts={}, &block) 975: associate(:one_to_many, name, opts, &block) 976: end
Shortcut for adding a one_to_one association, see #.
# File lib/sequel/model/associations.rb, line 979 979: def one_to_one(name, opts={}, &block) 980: associate(:one_to_one, name, opts, &block) 981: end
Use a window function to limit the results of the eager loading dataset.
# File lib/sequel/model/associations.rb, line 1038 1038: def apply_window_function_eager_limit_strategy(ds, opts) 1039: rn = ds.row_number_column 1040: limit, offset = opts.limit_and_offset 1041: ds = ds.unordered.select_append{row_number(:over, :partition=>opts.eager_loading_predicate_key, :order=>ds.opts[:order]){}.as(rn)}.from_self 1042: ds = if opts[:type] == :one_to_one 1043: ds.where(rn => 1) 1044: elsif offset 1045: offset += 1 1046: ds.where(rn => (offset...(offset+limit))) 1047: else 1048: ds.where{SQL::Identifier.new(rn) <= limit} 1049: end 1050: end
The module to use for the association’s methods. Defaults to the overridable_methods_module.
# File lib/sequel/model/associations.rb, line 1054 1054: def association_module(opts={}) 1055: opts.fetch(:methods_module, overridable_methods_module) 1056: end
Add a method to the module included in the class, so the method can be easily overridden in the class itself while allowing for super to be called.
# File lib/sequel/model/associations.rb, line 1061 1061: def association_module_def(name, opts={}, &block) 1062: association_module(opts).module_eval{define_method(name, &block)} 1063: end
Add a private method to the module included in the class.
# File lib/sequel/model/associations.rb, line 1066 1066: def association_module_private_def(name, opts={}, &block) 1067: association_module_def(name, opts, &block) 1068: association_module(opts).send(:private, name) 1069: end
Add the add_ instance method
# File lib/sequel/model/associations.rb, line 1072 1072: def def_add_method(opts) 1073: association_module_def(opts.add_method, opts){|o,*args| add_associated_object(opts, o, *args)} 1074: end
Adds the association dataset methods to the association methods module.
# File lib/sequel/model/associations.rb, line 1077 1077: def def_association_dataset_methods(opts) 1078: # If a block is given, define a helper method for it, because it takes 1079: # an argument. This is unnecessary in Ruby 1.9, as that has instance_exec. 1080: association_module_private_def(opts.dataset_helper_method, opts, &opts[:block]) if opts[:block] 1081: association_module_private_def(opts._dataset_method, opts, &opts[:dataset]) 1082: association_module_def(opts.dataset_method, opts){_dataset(opts)} 1083: def_association_method(opts) 1084: end
Adds the association method to the association methods module.
# File lib/sequel/model/associations.rb, line 1087 1087: def def_association_method(opts) 1088: association_module_def(opts.association_method, opts){|*dynamic_opts, &block| load_associated_objects(opts, dynamic_opts[0], &block)} 1089: end
Configures many_to_many association reflection and adds the related association methods
# File lib/sequel/model/associations.rb, line 1092 1092: def def_many_to_many(opts) 1093: name = opts[:name] 1094: model = self 1095: left = (opts[:left_key] ||= opts.default_left_key) 1096: lcks = opts[:left_keys] = Array(left) 1097: right = (opts[:right_key] ||= opts.default_right_key) 1098: rcks = opts[:right_keys] = Array(right) 1099: left_pk = (opts[:left_primary_key] ||= self.primary_key) 1100: lcpks = opts[:left_primary_keys] = Array(left_pk) 1101: lpkc = opts[:left_primary_key_column] ||= left_pk 1102: lpkcs = opts[:left_primary_key_columns] ||= Array(lpkc) 1103: elk = opts.eager_loader_key 1104: raise(Error, "mismatched number of left composite keys: #{lcks.inspect} vs #{lcpks.inspect}") unless lcks.length == lcpks.length 1105: if opts[:right_primary_key] 1106: rcpks = Array(opts[:right_primary_key]) 1107: raise(Error, "mismatched number of right composite keys: #{rcks.inspect} vs #{rcpks.inspect}") unless rcks.length == rcpks.length 1108: end 1109: uses_lcks = opts[:uses_left_composite_keys] = lcks.length > 1 1110: uses_rcks = opts[:uses_right_composite_keys] = rcks.length > 1 1111: opts[:cartesian_product_number] ||= 1 1112: join_table = (opts[:join_table] ||= opts.default_join_table) 1113: left_key_alias = opts[:left_key_alias] ||= opts.default_associated_key_alias 1114: graph_jt_conds = opts[:graph_join_table_conditions] = opts.fetch(:graph_join_table_conditions, []).to_a 1115: opts[:graph_join_table_join_type] ||= opts[:graph_join_type] 1116: opts[:after_load].unshift(:array_uniq!) if opts[:uniq] 1117: opts[:dataset] ||= proc{opts.associated_class.inner_join(join_table, rcks.zip(opts.right_primary_keys) + lcks.zip(lcpks.map{|k| send(k)}))} 1118: 1119: opts[:eager_loader] ||= proc do |eo| 1120: h = eo[:key_hash][elk] 1121: rows = eo[:rows] 1122: rows.each{|object| object.associations[name] = []} 1123: r = rcks.zip(opts.right_primary_keys) 1124: l = [[opts.qualify(opts.join_table_alias, left), h.keys]] 1125: ds = model.eager_loading_dataset(opts, opts.associated_class.inner_join(join_table, r + l), nil, eo[:associations], eo) 1126: case opts.eager_limit_strategy 1127: when :window_function 1128: delete_rn = true 1129: rn = ds.row_number_column 1130: ds = apply_window_function_eager_limit_strategy(ds, opts) 1131: when :correlated_subquery 1132: ds = apply_correlated_subquery_eager_limit_strategy(ds, opts) do |xds| 1133: dsa = ds.send(:dataset_alias, 2) 1134: xds.inner_join(join_table, r + lcks.map{|k| [k, SQL::QualifiedIdentifier.new(opts.join_table_alias, k)]}, :table_alias=>dsa) 1135: end 1136: end 1137: ds.all do |assoc_record| 1138: assoc_record.values.delete(rn) if delete_rn 1139: hash_key = if uses_lcks 1140: left_key_alias.map{|k| assoc_record.values.delete(k)} 1141: else 1142: assoc_record.values.delete(left_key_alias) 1143: end 1144: next unless objects = h[hash_key] 1145: objects.each{|object| object.associations[name].push(assoc_record)} 1146: end 1147: if opts.eager_limit_strategy == :ruby 1148: limit, offset = opts.limit_and_offset 1149: rows.each{|o| o.associations[name] = o.associations[name].slice(offset||0, limit) || []} 1150: end 1151: end 1152: 1153: join_type = opts[:graph_join_type] 1154: select = opts[:graph_select] 1155: use_only_conditions = opts.include?(:graph_only_conditions) 1156: only_conditions = opts[:graph_only_conditions] 1157: conditions = opts[:graph_conditions] 1158: graph_block = opts[:graph_block] 1159: use_jt_only_conditions = opts.include?(:graph_join_table_only_conditions) 1160: jt_only_conditions = opts[:graph_join_table_only_conditions] 1161: jt_join_type = opts[:graph_join_table_join_type] 1162: jt_graph_block = opts[:graph_join_table_block] 1163: opts[:eager_grapher] ||= proc do |eo| 1164: ds = eo[:self] 1165: ds = ds.graph(join_table, use_jt_only_conditions ? jt_only_conditions : lcks.zip(lpkcs) + graph_jt_conds, :select=>false, :table_alias=>ds.unused_table_alias(join_table, [eo[:table_alias]]), :join_type=>jt_join_type, :implicit_qualifier=>eo[:implicit_qualifier], :from_self_alias=>ds.opts[:eager_graph][:master], &jt_graph_block) 1166: ds.graph(eager_graph_dataset(opts, eo), use_only_conditions ? only_conditions : opts.right_primary_keys.zip(rcks) + conditions, :select=>select, :table_alias=>eo[:table_alias], :join_type=>join_type, &graph_block) 1167: end 1168: 1169: def_association_dataset_methods(opts) 1170: 1171: return if opts[:read_only] 1172: 1173: association_module_private_def(opts._add_method, opts) do |o| 1174: h = {} 1175: lcks.zip(lcpks).each{|k, pk| h[k] = send(pk)} 1176: rcks.zip(opts.right_primary_key_methods).each{|k, pk| h[k] = o.send(pk)} 1177: _join_table_dataset(opts).insert(h) 1178: end 1179: association_module_private_def(opts._remove_method, opts) do |o| 1180: _join_table_dataset(opts).filter(lcks.zip(lcpks.map{|k| send(k)}) + rcks.zip(opts.right_primary_key_methods.map{|k| o.send(k)})).delete 1181: end 1182: association_module_private_def(opts._remove_all_method, opts) do 1183: _join_table_dataset(opts).filter(lcks.zip(lcpks.map{|k| send(k)})).delete 1184: end 1185: 1186: def_add_method(opts) 1187: def_remove_methods(opts) 1188: end
Configures many_to_one association reflection and adds the related association methods
# File lib/sequel/model/associations.rb, line 1191 1191: def def_many_to_one(opts) 1192: name = opts[:name] 1193: model = self 1194: opts[:key] = opts.default_key unless opts.include?(:key) 1195: key_column = key = opts[:key] 1196: cks = opts[:graph_keys] = opts[:keys] = Array(key) 1197: if opts[:key_column] 1198: key_column = opts[:key_column] 1199: opts[:eager_loader_key] ||= key_column 1200: opts[:graph_keys] = Array(key_column) 1201: end 1202: opts[:qualified_key] = opts.qualify_cur(key) 1203: if opts[:primary_key] 1204: cpks = Array(opts[:primary_key]) 1205: raise(Error, "mismatched number of composite keys: #{cks.inspect} vs #{cpks.inspect}") unless cks.length == cpks.length 1206: end 1207: uses_cks = opts[:uses_composite_keys] = cks.length > 1 1208: qualify = opts[:qualify] != false 1209: opts[:cartesian_product_number] ||= 0 1210: opts[:dataset] ||= proc do 1211: klass = opts.associated_class 1212: klass.filter(Array(opts.qualified_primary_key).zip(cks.map{|k| send(k)})) 1213: end 1214: opts[:eager_loader] ||= proc do |eo| 1215: h = eo[:key_hash][key_column] 1216: keys = h.keys 1217: # Default the cached association to nil, so any object that doesn't have it 1218: # populated will have cached the negative lookup. 1219: eo[:rows].each{|object| object.associations[name] = nil} 1220: # Skip eager loading if no objects have a foreign key for this association 1221: unless keys.empty? 1222: klass = opts.associated_class 1223: model.eager_loading_dataset(opts, klass.filter(opts.qualified_primary_key=>keys), nil, eo[:associations], eo).all do |assoc_record| 1224: hash_key = uses_cks ? opts.primary_key_methods.map{|k| assoc_record.send(k)} : assoc_record.send(opts.primary_key_method) 1225: next unless objects = h[hash_key] 1226: objects.each{|object| object.associations[name] = assoc_record} 1227: end 1228: end 1229: end 1230: 1231: join_type = opts[:graph_join_type] 1232: select = opts[:graph_select] 1233: use_only_conditions = opts.include?(:graph_only_conditions) 1234: only_conditions = opts[:graph_only_conditions] 1235: conditions = opts[:graph_conditions] 1236: graph_block = opts[:graph_block] 1237: graph_cks = opts[:graph_keys] 1238: opts[:eager_grapher] ||= proc do |eo| 1239: ds = eo[:self] 1240: ds.graph(eager_graph_dataset(opts, eo), use_only_conditions ? only_conditions : opts.primary_keys.zip(graph_cks) + conditions, eo.merge(:select=>select, :join_type=>join_type, :from_self_alias=>ds.opts[:eager_graph][:master]), &graph_block) 1241: end 1242: 1243: def_association_dataset_methods(opts) 1244: 1245: return if opts[:read_only] 1246: 1247: association_module_private_def(opts._setter_method, opts){|o| cks.zip(opts.primary_key_methods).each{|k, pk| send(:"#{k}=", (o.send(pk) if o))}} 1248: association_module_def(opts.setter_method, opts){|o| set_associated_object(opts, o)} 1249: end
Configures one_to_many and one_to_one association reflections and adds the related association methods
# File lib/sequel/model/associations.rb, line 1252 1252: def def_one_to_many(opts) 1253: one_to_one = opts[:type] == :one_to_one 1254: name = opts[:name] 1255: model = self 1256: key = (opts[:key] ||= opts.default_key) 1257: km = opts[:key_method] ||= opts[:key] 1258: cks = opts[:keys] = Array(key) 1259: primary_key = (opts[:primary_key] ||= self.primary_key) 1260: cpks = opts[:primary_keys] = Array(primary_key) 1261: pkc = opts[:primary_key_column] ||= primary_key 1262: pkcs = opts[:primary_key_columns] ||= Array(pkc) 1263: elk = opts.eager_loader_key 1264: raise(Error, "mismatched number of composite keys: #{cks.inspect} vs #{cpks.inspect}") unless cks.length == cpks.length 1265: uses_cks = opts[:uses_composite_keys] = cks.length > 1 1266: opts[:dataset] ||= proc do 1267: opts.associated_class.filter(Array(opts.qualified_key).zip(cpks.map{|k| send(k)})) 1268: end 1269: opts[:eager_loader] ||= proc do |eo| 1270: h = eo[:key_hash][elk] 1271: rows = eo[:rows] 1272: if one_to_one 1273: rows.each{|object| object.associations[name] = nil} 1274: else 1275: rows.each{|object| object.associations[name] = []} 1276: end 1277: reciprocal = opts.reciprocal 1278: klass = opts.associated_class 1279: filter_keys = opts.eager_loading_predicate_key 1280: ds = model.eager_loading_dataset(opts, klass.filter(filter_keys=>h.keys), nil, eo[:associations], eo) 1281: case opts.eager_limit_strategy 1282: when :distinct_on 1283: ds = ds.distinct(*filter_keys).order_prepend(*filter_keys) 1284: when :window_function 1285: delete_rn = true 1286: rn = ds.row_number_column 1287: ds = apply_window_function_eager_limit_strategy(ds, opts) 1288: when :correlated_subquery 1289: ds = apply_correlated_subquery_eager_limit_strategy(ds, opts) do |xds| 1290: xds.where(opts.associated_object_keys.map{|k| [SQL::QualifiedIdentifier.new(xds.first_source_alias, k), SQL::QualifiedIdentifier.new(xds.first_source_table, k)]}) 1291: end 1292: end 1293: ds.all do |assoc_record| 1294: assoc_record.values.delete(rn) if delete_rn 1295: hash_key = uses_cks ? km.map{|k| assoc_record.send(k)} : assoc_record.send(km) 1296: next unless objects = h[hash_key] 1297: if one_to_one 1298: objects.each do |object| 1299: unless object.associations[name] 1300: object.associations[name] = assoc_record 1301: assoc_record.associations[reciprocal] = object if reciprocal 1302: end 1303: end 1304: else 1305: objects.each do |object| 1306: object.associations[name].push(assoc_record) 1307: assoc_record.associations[reciprocal] = object if reciprocal 1308: end 1309: end 1310: end 1311: if opts.eager_limit_strategy == :ruby 1312: limit, offset = opts.limit_and_offset 1313: rows.each{|o| o.associations[name] = o.associations[name].slice(offset||0, limit) || []} 1314: end 1315: end 1316: 1317: join_type = opts[:graph_join_type] 1318: select = opts[:graph_select] 1319: use_only_conditions = opts.include?(:graph_only_conditions) 1320: only_conditions = opts[:graph_only_conditions] 1321: conditions = opts[:graph_conditions] 1322: opts[:cartesian_product_number] ||= one_to_one ? 0 : 1 1323: graph_block = opts[:graph_block] 1324: opts[:eager_grapher] ||= proc do |eo| 1325: ds = eo[:self] 1326: ds = ds.graph(eager_graph_dataset(opts, eo), use_only_conditions ? only_conditions : cks.zip(pkcs) + conditions, eo.merge(:select=>select, :join_type=>join_type, :from_self_alias=>ds.opts[:eager_graph][:master]), &graph_block) 1327: # We only load reciprocals for one_to_many associations, as other reciprocals don't make sense 1328: ds.opts[:eager_graph][:reciprocals][eo[:table_alias]] = opts.reciprocal 1329: ds 1330: end 1331: 1332: def_association_dataset_methods(opts) 1333: 1334: ck_nil_hash ={} 1335: cks.each{|k| ck_nil_hash[k] = nil} 1336: 1337: unless opts[:read_only] 1338: validate = opts[:validate] 1339: 1340: if one_to_one 1341: association_module_private_def(opts._setter_method, opts) do |o| 1342: up_ds = _apply_association_options(opts, opts.associated_class.filter(cks.zip(cpks.map{|k| send(k)}))) 1343: if o 1344: up_ds = up_ds.exclude(o.pk_hash) 1345: cks.zip(cpks).each{|k, pk| o.send(:"#{k}=", send(pk))} 1346: end 1347: checked_transaction do 1348: up_ds.update(ck_nil_hash) 1349: o.save(:validate=>validate) || raise(Sequel::Error, "invalid associated object, cannot save") if o 1350: end 1351: end 1352: association_module_def(opts.setter_method, opts){|o| set_one_to_one_associated_object(opts, o)} 1353: else 1354: association_module_private_def(opts._add_method, opts) do |o| 1355: cks.zip(cpks).each{|k, pk| o.send(:"#{k}=", send(pk))} 1356: o.save(:validate=>validate) || raise(Sequel::Error, "invalid associated object, cannot save") 1357: end 1358: def_add_method(opts) 1359: 1360: association_module_private_def(opts._remove_method, opts) do |o| 1361: cks.each{|k| o.send(:"#{k}=", nil)} 1362: o.save(:validate=>validate) || raise(Sequel::Error, "invalid associated object, cannot save") 1363: end 1364: association_module_private_def(opts._remove_all_method, opts) do 1365: _apply_association_options(opts, opts.associated_class.filter(cks.zip(cpks.map{|k| send(k)}))).update(ck_nil_hash) 1366: end 1367: def_remove_methods(opts) 1368: end 1369: end 1370: end
Alias of def_one_to_many, since they share pretty much the same code.
# File lib/sequel/model/associations.rb, line 1373 1373: def def_one_to_one(opts) 1374: def_one_to_many(opts) 1375: end
Add the remove_ and remove_all instance methods
# File lib/sequel/model/associations.rb, line 1378 1378: def def_remove_methods(opts) 1379: association_module_def(opts.remove_method, opts){|o,*args| remove_associated_object(opts, o, *args)} 1380: association_module_def(opts.remove_all_method, opts){|*args| remove_all_associated_objects(opts, *args)} 1381: end
Return dataset to graph into given the association reflection, applying the :callback option if set.
# File lib/sequel/model/associations.rb, line 1384 1384: def eager_graph_dataset(opts, eager_options) 1385: ds = opts.associated_class.dataset 1386: if cb = eager_options[:callback] 1387: ds = cb.call(ds) 1388: end 1389: ds 1390: end
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