Class: Trix51::Tuple

Inherits:
Trix51 show all
Defined in:
lib/trix51db.rb

Overview

Represents a single record from the database.

Constant Summary

Constants inherited from Trix51

KEY_JOIN, META_PREFIX, RECORD_PREFIX, SEQ_PREFIX

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Trix51

add_connection, add_helper, class_to_database, class_to_table, connections, create_helper_code, debug, defer_classref, defer_classref=, error, fatal, info, table_to_database, warn

Constructor Details

#initialize(table, urid, anonhash = nil) ⇒ Tuple

Create a new tuple object

Arguments:

table

A Trix51::Table object

urid

A unique record identifier

anonhash

An optional anonymous hash containing the data for the tuple.



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# File 'lib/trix51db.rb', line 363

def initialize( table, urid, anonhash=nil )
  @table = table
  @data = Marshal.load( @table.dbref[urid] ) if anonhash.nil?
  @data = anonhash if not anonhash.nil?
  @newdata = {}
  @urid = urid
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(methodId, *args) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 376

def method_missing( methodId, *args ) #:nodoc:
  
  name = methodId.to_s
  
  basename = name.gsub( '=', '' ).to_sym
  
  if not @table.structure[basename].nil? then
    #return @data[name]
    if name.match( '=' ) then
	@newdata[basename] = args.shift
	#puts "setting value of #{basename} to #{@newdata[basename]}.."
    else
	return @newdata[basename] || @data[basename] if ['string', 'integer', 'datetime'].include?( self.table.structure[basename][:datatype])
                                                                                           
	# derived fields
	dt = self.table.structure[basename][:datatype]
	"------------------------------"
                                                                                         
	if dt == 'record' then
  # handle one to one   
  #pp self.table.structure[basename][:table]
  dbref = Trix51.table_to_database( self.table.structure[basename][:table] )
  #pp dbref
  tblref = dbref.get_table( self.table.structure[basename][:table] )
  srcref = self.table.structure[basename][:source]
  dstref = self.table.structure[basename][:dest]   
  return tblref.first( dstref => @data[srcref] )
	end     
	
	if dt == 'resultset' then
  dbref = Trix51.table_to_database( self.table.structure[basename][:table] )
  tblref = dbref.get_table( self.table.structure[basename][:table] )
  srcref = self.table.structure[basename][:source]
  dstref = self.table.structure[basename][:dest] 
  #puts "#{tblref.tablename}.#{dstref} = #{@data[srcref]}"
  h = { dstref => @data[srcref].to_s }
  return tblref.select_hash( h )
	end
	
	if dt == 'calculated' then
 c = self.table.structure[basename][:calculation] 
 return eval( c ).to_s
	end
                                                                                           
    end
  else
    raise Trix51::NotFoundError, "No such field #{methodId}"
  end
  
end

Instance Attribute Details

#data ⇒ Object

Accessors for the tuple class.



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# File 'lib/trix51db.rb', line 473

def data
  @data
end

#table ⇒ Object

Accessors for the tuple class.



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# File 'lib/trix51db.rb', line 473

def table
  @table
end

#urid ⇒ Object

Accessors for the tuple class.



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# File 'lib/trix51db.rb', line 473

def urid
  @urid
end

Instance Method Details

#has_updates? ⇒ Boolean

Returns true or false if the record has been updated.

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 372

def has_updates?
  return (@newdata.keys.length > 0)
end

#update ⇒ Object

post any record updates, update any indexes and keys.



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# File 'lib/trix51db.rb', line 428

def update
  
  ref = @data.merge( @newdata ) { |key, oldval, newval|
   (not newval.nil?) ? newval : oldval
  }
  
  # ref now represents the new record
  newurid = self.table.get_hash_key( ref )
  
  @newdata.each_pair do |fieldname,fieldvalue|
    raise Trix51::ConstraintError, "Update would violate unique constraint on field #{fieldname}" unless self.table.index_chk_unique_update( fieldname, fieldvalue, @urid )
  end
  
  if newurid == @urid then
    self.table.index_update( @urid, newurid, @newdata )
    # simple update
    self.table.dbref[ @urid ] = Marshal.dump( ref )
    @data = ref
    @newdata = {}
    
    #puts "Key is unchanged"
    
    return true
  end
  
  # if we are here the key has changed
  # make sure the new one does not exist
  if not self.table.dbref[ newurid ].nil? then
    @newdata = {}
    raise Trix51::ConstraintError, "Update to record would violate unique contraints"
  end
  
  # if we are here, add the new record
  self.table.index_update( @urid, newurid, @newdata )
  #puts "Re-keying the record due to a change in unique key"
  self.table.dbref[ newurid ] = Marshal.dump( ref )
  @data = @newdata
  @newdata = {}
  @urid = newurid
  
  return true
  
end