module ActiveRecord # :stopdoc: module ConnectionAdapters # An abstract definition of a column in a table. class Column attr_reader :name, :default, :sql_type_metadata, :null, :table_name, :default_function, :collation, :comment delegate :precision, :scale, :limit, :type, :sql_type, to: :sql_type_metadata, allow_nil: true # Instantiates a new column in the table. # # +name+ is the column's name, such as supplier_id in supplier_id int. # +default+ is the type-casted default value, such as +new+ in sales_stage varchar(20) default 'new'. # +sql_type_metadata+ is various information about the type of the column # +null+ determines if this column allows +NULL+ values. def initialize(name, default, sql_type_metadata = nil, null = true, table_name = nil, default_function = nil, collation = nil, comment: nil) @name = name.freeze @table_name = table_name @sql_type_metadata = sql_type_metadata @null = null @default = default @default_function = default_function @collation = collation @comment = comment end def has_default? !default.nil? || default_function end def bigint? /\Abigint\b/.match?(sql_type) end # Returns the human name of the column name. # # ===== Examples # Column.new('sales_stage', ...).human_name # => 'Sales stage' def human_name Base.human_attribute_name(@name) end def init_with(coder) @name = coder["name"] @table_name = coder["table_name"] @sql_type_metadata = coder["sql_type_metadata"] @null = coder["null"] @default = coder["default"] @default_function = coder["default_function"] @collation = coder["collation"] @comment = coder["comment"] end def encode_with(coder) coder["name"] = @name coder["table_name"] = @table_name coder["sql_type_metadata"] = @sql_type_metadata coder["null"] = @null coder["default"] = @default coder["default_function"] = @default_function coder["collation"] = @collation coder["comment"] = @comment end def ==(other) other.is_a?(Column) && attributes_for_hash == other.attributes_for_hash end alias :eql? :== def hash attributes_for_hash.hash end protected def attributes_for_hash [self.class, name, default, sql_type_metadata, null, table_name, default_function, collation] end end class NullColumn < Column def initialize(name) super(name, nil) end end end # :startdoc: end