class Arel::Table - arel-4.0.2 Documentation

# class Arel::Table

### Attributes

engine[RW]
aliases[RW]
engine[RW]
name[RW]
table_alias[RW]
table_name[RW]

### Public Class Methods

new(name, engine = Table.engine) click to toggle source

    # File lib/arel/table.rb, line 14
    def initialize name, engine = Table.engine
      @name    = name.to_s
      @engine  = engine
      @columns = nil
      @aliases = []
      @table_alias = nil
      @primary_key = nil

      if Hash === engine
        @engine  = engine[:engine] || Table.engine

        # Sometime AR sends an :as parameter to table, to let the table know
        # that it is an Alias.  We may want to override new, and return a
        # TableAlias node?
        @table_alias = engine[:as] unless engine[:as].to_s == @name
      end
    end

### Public Instance Methods

==(other)
Alias for: eql?
[](name) click to toggle source

    # File lib/arel/table.rb, line 114
    def [] name
      ::Arel::Attribute.new self, name
    end

alias(name = " click to toggle source

    # File lib/arel/table.rb, line 45
    def alias name = "#{self.name}_2"
      Nodes::TableAlias.new(self, name).tap do |node|
        @aliases << node
      end
    end

columns() click to toggle source

    # File lib/arel/table.rb, line 103
        def columns
          if $VERBOSE
            warn <<-eowarn
    (#{caller.first}) Arel::Table#columns is deprecated and will be removed in
    Arel 4.0.0 with no replacement.  PEW PEW PEW!!!
            eowarn
          end
          @columns ||=
            attributes_for @engine.connection.columns(@name, "#{@name} Columns")
        end

eql?(other) click to toggle source

    # File lib/arel/table.rb, line 133
    def eql? other
      self.class == other.class &&
        self.name == other.name &&
        self.engine == other.engine &&
        self.aliases == other.aliases &&
        self.table_alias == other.table_alias
    end

Also aliased as: ==
from(table) click to toggle source

    # File lib/arel/table.rb, line 51
    def from table
      SelectManager.new(@engine, table)
    end

group(*columns) click to toggle source

    # File lib/arel/table.rb, line 75
    def group *columns
      from(self).group(*columns)
    end

hash() click to toggle source

    # File lib/arel/table.rb, line 126
    def hash
      # Perf note: aliases, table alias and engine is excluded from the hash
      #  aliases can have a loop back to this table breaking hashes in parent
      #  relations, for the vast majority of cases @name is unique to a query
      @name.hash
    end

having(expr) click to toggle source

    # File lib/arel/table.rb, line 99
    def having expr
      from(self).having expr
    end

insert_manager() click to toggle source

    # File lib/arel/table.rb, line 122
    def insert_manager
      InsertManager.new(@engine)
    end

join(relation, klass = Nodes::InnerJoin) click to toggle source

    # File lib/arel/table.rb, line 63
    def join relation, klass = Nodes::InnerJoin
      return from(self) unless relation

      case relation
      when String, Nodes::SqlLiteral
        raise if relation.blank?
        klass = Nodes::StringJoin
      end

      from(self).join(relation, klass)
    end

joins(manager) click to toggle source

    # File lib/arel/table.rb, line 55
    def joins manager
      if $VERBOSE
        warn "joins is deprecated and will be removed in 4.0.0"
        warn "please remove your call to joins from #{caller.first}"
      end
      nil
    end

order(*expr) click to toggle source

    # File lib/arel/table.rb, line 79
    def order *expr
      from(self).order(*expr)
    end

primary_key() click to toggle source

    # File lib/arel/table.rb, line 32
        def primary_key
          if $VERBOSE
            warn <<-eowarn
    primary_key (#{caller.first}) is deprecated and will be removed in Arel 4.0.0
            eowarn
          end
          @primary_key ||= begin
            primary_key_name = @engine.connection.primary_key(name)
            # some tables might be without primary key
            primary_key_name && self[primary_key_name]
          end
        end

project(*things) click to toggle source

    # File lib/arel/table.rb, line 87
    def project *things
      from(self).project(*things)
    end

select_manager() click to toggle source

    # File lib/arel/table.rb, line 118
    def select_manager
      SelectManager.new(@engine)
    end

skip(amount) click to toggle source

    # File lib/arel/table.rb, line 95
    def skip amount
      from(self).skip amount
    end

take(amount) click to toggle source

    # File lib/arel/table.rb, line 91
    def take amount
      from(self).take amount
    end

where(condition) click to toggle source

    # File lib/arel/table.rb, line 83
    def where condition
      from(self).where condition
    end

### Private Instance Methods

attributes_for(columns) click to toggle source

    # File lib/arel/table.rb, line 144
    def attributes_for columns
      return nil unless columns

      columns.map do |column|
        Attributes.for(column).new self, column.name.to_sym
      end
    end