Returns a hash where the keys are column names and the values are default values when instantiating the AR object for this table.
# File lib/active_record/model_schema.rb, line 242 242: def column_defaults 243: @column_defaults ||= Hash[columns.map { |c| [c.name, c.default] }] 244: end
Returns an array of column names as strings.
# File lib/active_record/model_schema.rb, line 247 247: def column_names 248: @column_names ||= columns.map { |column| column.name } 249: end
Returns an array of column objects for the table associated with this class.
# File lib/active_record/model_schema.rb, line 227 227: def columns 228: @columns ||= connection.schema_cache.columns[table_name].map do |col| 229: col = col.dup 230: col.primary = (col.name == primary_key) 231: col 232: end 233: end
Returns a hash of column objects for the table associated with this class.
# File lib/active_record/model_schema.rb, line 236 236: def columns_hash 237: @columns_hash ||= Hash[columns.map { |c| [c.name, c] }] 238: end
Returns an array of column objects where the primary id, all columns ending in “_id” or “_count”, and columns used for single table inheritance have been removed.
# File lib/active_record/model_schema.rb, line 253 253: def content_columns 254: @content_columns ||= columns.reject { |c| c.primary || c.name =~ /(_id|_count)$/ || c.name == inheritance_column } 255: end
The name of the column containing the object’s class when Single Table Inheritance is used
# File lib/active_record/model_schema.rb, line 160 160: def inheritance_column 161: if self == Base 162: 'type' 163: else 164: (@inheritance_column ||= nil) || superclass.inheritance_column 165: end 166: end
Sets the value of inheritance_column
# File lib/active_record/model_schema.rb, line 173 173: def inheritance_column=(value) 174: @original_inheritance_column = inheritance_column 175: @inheritance_column = value.to_s 176: end
Returns a quoted version of the table name, used to construct SQL statements.
# File lib/active_record/model_schema.rb, line 136 136: def quoted_table_name 137: @quoted_table_name ||= connection.quote_table_name(table_name) 138: end
Resets all the cached information about columns, which will cause them to be reloaded on the next request.
The most common usage pattern for this method is probably in a migration, when just after creating a table you want to populate it with some default values, eg:
class CreateJobLevels < ActiveRecord::Migration def up create_table :job_levels do |t| t.integer :id t.string :name t.timestamps end JobLevel.reset_column_information %w{assistant executive manager director}.each do |type| JobLevel.create(:name => type) end end def down drop_table :job_levels end end
# File lib/active_record/model_schema.rb, line 297 297: def reset_column_information 298: connection.clear_cache! 299: undefine_attribute_methods 300: connection.schema_cache.clear_table_cache!(table_name) if table_exists? 301: 302: @column_names = @content_columns = @column_defaults = @columns = @columns_hash = nil 303: @dynamic_methods_hash = @inheritance_column = nil 304: @arel_engine = @relation = nil 305: end
# File lib/active_record/model_schema.rb, line 182 182: def sequence_name 183: if base_class == self 184: @sequence_name ||= reset_sequence_name 185: else 186: (@sequence_name ||= nil) || base_class.sequence_name 187: end 188: end
Sets the name of the sequence to use when generating ids to the given value, or (if the value is nil or false) to the value returned by the given block. This is required for Oracle and is useful for any database which relies on sequences for primary key generation.
If a sequence name is not explicitly set when using Oracle or Firebird, it will default to the commonly used pattern of: #{table_name}_seq
If a sequence name is not explicitly set when using PostgreSQL, it will discover the sequence corresponding to your primary key for you.
class Project < ActiveRecord::Base self.sequence_name = "projectseq" # default would have been "project_seq" end
# File lib/active_record/model_schema.rb, line 212 212: def sequence_name=(value) 213: @original_sequence_name = @sequence_name if defined?(@sequence_name) 214: @sequence_name = value.to_s 215: end
Indicates whether the table associated with this class exists
# File lib/active_record/model_schema.rb, line 222 222: def table_exists? 223: connection.schema_cache.table_exists?(table_name) 224: end
Guesses the table name (in forced lower-case) based on the name of the class in the inheritance hierarchy descending directly from ActiveRecord::Base. So if the hierarchy looks like: Reply < Message < ActiveRecord::Base, then Message is used to guess the table name even when called on Reply. The rules used to do the guess are handled by the Inflector class in Active Support, which knows almost all common English inflections. You can add new inflections in config/initializers/inflections.rb.
Nested classes are given table names prefixed by the singular form of the parent’s table name. Enclosing modules are not considered.
class Invoice < ActiveRecord::Base end file class table_name invoice.rb Invoice invoices class Invoice < ActiveRecord::Base class Lineitem < ActiveRecord::Base end end file class table_name invoice.rb Invoice::Lineitem invoice_lineitems module Invoice class Lineitem < ActiveRecord::Base end end file class table_name invoice/lineitem.rb Invoice::Lineitem lineitems
Additionally, the class-level table_name_prefix is prepended and the table_name_suffix is appended. So if you have “myapp_” as a prefix, the table name guess for an Invoice class becomes “myapp_invoices“. Invoice::Lineitem becomes “myapp_invoice_lineitems“.
You can also set your own table name explicitly:
class Mouse < ActiveRecord::Base self.table_name = "mice" end
Alternatively, you can override the table_name method to define your own computation. (Possibly using super to manipulate the default table name.) Example:
class Post < ActiveRecord::Base def self.table_name "special_" + super end end Post.table_name # => "special_posts"
# File lib/active_record/model_schema.rb, line 103 103: def table_name 104: reset_table_name unless defined?(@table_name) 105: @table_name 106: end
Sets the table name explicitly. Example:
class Project < ActiveRecord::Base self.table_name = "project" end
You can also just define your own self.table_name method; see the documentation for ActiveRecord::Base#table_name.
# File lib/active_record/model_schema.rb, line 120 120: def table_name=(value) 121: @original_table_name = @table_name if defined?(@table_name) 122: @table_name = value && value.to_s 123: @quoted_table_name = nil 124: @arel_table = nil 125: @relation = Relation.new(self, arel_table) 126: end
Computes and returns a table name according to default conventions.
# File lib/active_record/model_schema.rb, line 321 321: def compute_table_name 322: base = base_class 323: if self == base 324: # Nested classes are prefixed with singular parent table name. 325: if parent < ActiveRecord::Base && !parent.abstract_class? 326: contained = parent.table_name 327: contained = contained.singularize if parent.pluralize_table_names 328: contained += '_' 329: end 330: "#{full_table_name_prefix}#{contained}#{undecorated_table_name(name)}#{table_name_suffix}" 331: else 332: # STI subclasses always use their superclass' table. 333: base.table_name 334: end 335: end
# File lib/active_record/model_schema.rb, line 355 355: def deprecated_original_property_getter(property) 356: ActiveSupport::Deprecation.warn("original_#{property} is deprecated. Define self.#{property} and call super instead.") 357: 358: if !instance_variable_defined?("@original_#{property}") && respond_to?("reset_#{property}") 359: send("reset_#{property}") 360: else 361: instance_variable_get("@original_#{property}") 362: end 363: end
# File lib/active_record/model_schema.rb, line 337 337: def deprecated_property_setter(property, value, block) 338: if block 339: ActiveSupport::Deprecation.warn( 340: "Calling set_#{property} is deprecated. If you need to lazily evaluate " "the #{property}, define your own `self.#{property}` class method. You can use `super` " "to get the default #{property} where you would have called `original_#{property}`." 341: ) 342: 343: define_attr_method property, value, false, &block 344: else 345: ActiveSupport::Deprecation.warn( 346: "Calling set_#{property} is deprecated. Please use `self.#{property} = 'the_name'` instead." 347: ) 348: 349: define_attr_method property, value, false 350: end 351: end
Guesses the table name, but does not decorate it with prefix and suffix information.
# File lib/active_record/model_schema.rb, line 314 314: def undecorated_table_name(class_name = base_class.name) 315: table_name = class_name.to_s.demodulize.underscore 316: table_name = table_name.pluralize if pluralize_table_names 317: table_name 318: end
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