Class: Arel::Table

Inherits:
Object
  • Object
show all
Includes:
Recursion::BaseCase, Relation
Defined in:
lib/arel/engines/sql/relations/table.rb

Constant Summary collapse

@@engine = 
nil
@@tables = 
nil

Instance Attribute Summary collapse

Attributes included from Relation

#count

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Relation

#[], #alias, #bind, #call, #compiler, #delete, #each, #exclusion_predicate_sql, #externalizable?, #externalize, #find_attribute_matching_name, #from, #from_clauses, #group_clauses, #groupings, #having_clauses, #havings, #inclusion_predicate_sql, #insert, #inserts, #join, #join?, #joins, #lock, #locked, #order_clauses, #orders, #outer_join, #position_of, #primary_key, #project, #projections, #select_clauses, #session, #skip, #skipped, #sources, #take, #taken, #to_sql, #update, #where, #where_clauses, #wheres

Methods included from Recursion::BaseCase

#table, #table_sql

Constructor Details

#initialize(name, options = {}) ⇒ Table

Returns a new instance of Table.



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# File 'lib/arel/engines/sql/relations/table.rb', line 17

def initialize(name, options = {})
  @name = name.to_s
  @table_exists = nil
  @table_alias = nil
  @christener = Sql::Christener.new
  @attributes = nil
  @matching_attributes = nil

  if options.is_a?(Hash)
    @options = options
    @engine = options[:engine] || Table.engine

    if options[:as]
      as = options[:as].to_s
      @table_alias = as unless as == @name
    end
  else
    @engine = options # Table.new('foo', engine)
  end

  if @engine.connection
    begin
      require "arel/engines/sql/compilers/#{@engine.adapter_name.downcase}_compiler"
    rescue LoadError
      begin
        # try to load an externally defined compiler, in case this adapter has defined the compiler on its own.
        require "#{@engine.adapter_name.downcase}/arel_compiler"
      rescue LoadError
        raise "#{@engine.adapter_name} is not supported by Arel."
      end
    end

    @@tables ||= engine.connection.tables
  end
end

Instance Attribute Details

#christener ⇒ Object (readonly)

Returns the value of attribute christener.



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# File 'lib/arel/engines/sql/relations/table.rb', line 15

def christener
  @christener
end

#engine ⇒ Object (readonly)

Returns the value of attribute engine.



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# File 'lib/arel/engines/sql/relations/table.rb', line 15

def engine
  @engine
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/arel/engines/sql/relations/table.rb', line 15

def name
  @name
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/arel/engines/sql/relations/table.rb', line 15

def options
  @options
end

#table_alias ⇒ Object (readonly)

Returns the value of attribute table_alias.



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# File 'lib/arel/engines/sql/relations/table.rb', line 15

def table_alias
  @table_alias
end

Class Method Details

.engine ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 8

def engine; @@engine; end

.engine=(e) ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 9

def engine= e; @@engine = e; end

.tables ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 11

def tables; @@tables; end

.tables=(e) ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 12

def tables= e; @@tables = e; end

Instance Method Details

#as(table_alias) ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 53

def as(table_alias)
  Table.new(name, options.merge(:as => table_alias))
end

#attributes ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 61

def attributes
  return @attributes if @attributes
  if table_exists?
    attrs = columns.collect do |column|
      Sql::Attributes.for(column).new(column, self, column.name.to_sym)
    end
    @attributes = Header.new(attrs)
  else
    Header.new
  end
end

#column_for(attribute) ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 73

def column_for(attribute)
  has_attribute?(attribute) and columns.detect { |c| c.name == attribute.name.to_s }
end

#columns ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 77

def columns
  @columns ||= engine.connection.columns(name, "#{name} Columns")
end

#reset ⇒ Object 



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# File 'lib/arel/engines/sql/relations/table.rb', line 81

def reset
  @columns = nil
  @attributes = Header.new([])
end

#table_exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/arel/engines/sql/relations/table.rb', line 57

def table_exists?
  @table_exists ||= @@tables.include?(name) || engine.connection.table_exists?(name)
end