Class: Trix51::TupleSet

Inherits:
Object
  • Object
show all
Defined in:
lib/trix51db.rb

Overview

This class represents a set of records which can either be a table, query result, or the result of a group expression.

Direct Known Subclasses

ResultSet, Table

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(tablename, dataref, options) ⇒ TupleSet

Creates a new TupleSet object, the core class for tables / query results.



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# File 'lib/trix51db.rb', line 482

def initialize( tablename, dataref, options )
  @tablename = tablename
  @dbref = dataref
  @options = {}
  @indices = {}
  @sort_order = nil
  @options = options
  @updateable = false
  @meta = nil
  if self.table? then
    #pp "table"
    @updateable = true
    @meta = self.meta
  else
    @meta = {}
    #pp "query or view"
    @meta[:tablename] = '__query'
    self.clone_structure( @options[:tableref] )
    @meta[:classname] = 'Trix51::Tuple'
  end
  
  #pp @meta
  
  @classname = @meta[:classname] || 'Trix51::Tuple'
  
  #pp @classname
  
  if @classname != 'Trix51::Tuple' then
      eval( 
"
class #{@classname} < Trix51::Tuple	      
      
end
", BND
	    )
  end
  
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(meth, *args) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 932

def method_missing( meth, *args ) #:nodoc:
  name = meth.to_s
  
  if m = name.match( /^select_by_(.+)/ ) then
    
    fields = m[1].split('_and_')
    h = {}
    while fields.length > 0 do
	n = fields.shift
	v = args.shift
	h[n] = v
    end
    
    return self.select_hash( h )

  end
 
  if m = name.match( /^delete_by_(.+)/ ) then
    
    fields = m[1].split('_and_')
    h = {}
    while fields.length > 0 do
	n = fields.shift
	v = args.shift
	h[n] = v
    end
    
    return self.delete_hash( h )

  end
  
  if m = name.match( /^update_by_(.+)/ ) then
    
    fields = m[1].split('_and_')
    h = {}
    while fields.length > 0 do
	n = fields.shift
	v = args.shift
	h[n] = v
    end
    
    matches = self.select_hash( h )
    
    matches.each { |record|
      yield record
      record.update if record.has_updates?
    }
  
    return matches.length

  end	  
  
end

Instance Attribute Details

#classname ⇒ Object

Key accessors for the tupleset class.



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# File 'lib/trix51db.rb', line 1818

def classname
  @classname
end

#dbref ⇒ Object

Key accessors for the tupleset class.



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# File 'lib/trix51db.rb', line 1818

def dbref
  @dbref
end

#indices ⇒ Object

Key accessors for the tupleset class.



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# File 'lib/trix51db.rb', line 1818

def indices
  @indices
end

#tablename ⇒ Object

Key accessors for the tupleset class.



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# File 'lib/trix51db.rb', line 1818

def tablename
  @tablename
end

Instance Method Details

#[](index) ⇒ Object

Returns table record at index.



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# File 'lib/trix51db.rb', line 1629

def [](index)
  keys = []
  self.sorted_keys.each do |k|
    keys.push( k ) if self.table_record?(k)
  end
  
  return nil if (keys.count == 0) or (keys.count <= index)
  
  urid = keys[ index ]
  
  return init_record( urid )
end

#all ⇒ Object

Returns all the records.



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# File 'lib/trix51db.rb', line 832

def all
  return self.select_hash( {} )
end

#args_to_hash(*args) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 846

def args_to_hash( *args ) #:nodoc:
  h = {}
  args.each { |rec|
    rec.each_pair { |k,v|
      h[k] = v
    }
  }
  #pp h
  return h
end

#build_sorted_keys(field, dir = 'asc') ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 545

def build_sorted_keys( field, dir='asc' ) #:nodoc:
  # sort records by list of fields
  idx = self.build_temp_idx( field )
  sk = []
  idx.keys.sort.each do |fieldvalue|
    keyref = idx[fieldvalue]
    keyref.each do |key|
      sk.push( key )
    end
  end
  return sk if dir == 'asc'
  return sk.reverse if dir == 'desc'
end

#build_temp_idx(field) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 521

def build_temp_idx( field ) #:nodoc:
  
  if (self.indexed?( field )) and (not self.indices[field].nil?) and (field != :random) then
    return @indices[field].clone
  end
  
  res = {}
  self.dbref.each_pair { |k, v|
    next unless self.table_record?( k )
    record = {}
    if v.class.name == 'String' then
      record = Marshal.load( v )
    else
	record = v.data
    end
    rv = record[field] if field != :random
    rv = rand() if field == :random
    rlist = res[rv] || []
    rlist.push( k )
    res[rv] = rlist
  }
  return res
end

#check_required_fields(hashdata) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 892

def check_required_fields( hashdata ) #:nodoc:
  
  # make sure all required fields are populated
  self.structure.each_key { |key|
    next if (not self.structure[key][:key] == true) and (not self.structure[key][:required] == true)
    raise Trix51::ConstraintError, "required or key field #{self.tablename}.#{key} is nil" if hashdata[key].nil?
    raise Trix51::ConstraintError, "unique constraint violated for field #{self.tablename}.#{key} [#{hashdata[key]}]" if not self.index_chk_unique( key, hashdata[key] )
  }
  
end

#clone_structure(tupleset) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 587

def clone_structure( tupleset ) #:nodoc:
  @meta[:structure] = tupleset.structure.clone
end

#column_add(name, spec) ⇒ Object

Add a column to the table.



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# File 'lib/trix51db.rb', line 1140

def column_add( name, spec )
  
  if not @meta[:structure][name].nil? then
    raise Trix51::ExistsError, "Column #{name} already exists"
  end
  
  # add in and reparse
  @meta[:structure][name] = spec
  self.meta = @meta
  @meta = self.meta
  
  #pp @meta
  
  need_rebuild = false
  
  # now assign default
  @dbref.each_pair do |k,v|
      next unless self.table_record?( k )
      
      record = Marshal.load( v )
      record[name] = self.default( name )
      v = Marshal.dump( record )
      newk = self.get_hash_key( record )
      if newk != k then
	@dbref.delete(k)
	need_rebuild = true
      end
      
      @dbref[ newk ] = v
  end
  
  @indices.clear if need_rebuild
      
end

#column_remove(name) ⇒ Object

Remove a column from the table.



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# File 'lib/trix51db.rb', line 1176

def column_remove( name )
  
  if @meta[:structure][name].nil? then
    raise Trix51::NotFoundError, "Column #{name} does not exist"
  end
  
  # add in and reparse
  @meta[:structure].delete(name)
  self.meta = @meta
  @meta = self.meta
  
  need_rebuild = false
  
  # now assign default
  @dbref.each_pair do |k,v|
      next unless self.table_record?( k )
      
      record = Marshal.load( v )
      record.delete( name ) if record.has_key?( name )
      v = Marshal.dump( record )
      newk = self.get_hash_key( record )
      if newk != k then
	@dbref.delete(k)
	need_rebuild = true
      end
      
      @dbref[ newk ] = v
  end
    
  @indices.clear if need_rebuild
end

#column_update(name, spec) ⇒ Object

Update the specification for a column.



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# File 'lib/trix51db.rb', line 1209

def column_update( name, spec )
  
  if @meta[:structure][name].nil? then
    raise Trix51::NotFoundError, "Column #{name} does not exist"
  end
  
  oldspec = @meta[:structure][name]
  newspec = Marshal.load( Marshal.dump( spec ) )
  
  uval = {}
  ukey = {}
  
  @dbref.each_pair do |k,v|
    
    next unless self.table_record?( k )
    
    record = Marshal.load( v )
    value = record[name]
    
    #  test field uniqueness
    if newspec[:unique] then
      raise Trix51::ConstraintError, "Field definition change would create a unique key violation condition" if not uval[value].nil?
      uval[value] = 1
    end
    
    # type check
    nrecord = record.clone
    if newspec[:datatype] != oldspec[:datatype] then
      begin
	nrecord[name] = self.convert_type( value, newspec[:datatype] ).to_s
	#pp nrecord
	newurid = self.get_hash_key( nrecord )
	if not ukey[newurid].nil? then
	  raise Trix51::ConstraintError, "Field definition change would violate uniqueness of keys"
	end
	ukey[newurid] = 1
      rescue 
	raise Trix51::TypeError, "Type conversion from #{oldspec[:datatype]} to #{newspec[:datatype]} would barf..."
      end
    end
    
  end
  
  # update will be okay
  @meta[:structure][name] = newspec
  self.meta = @meta
  @meta = self.meta
  
  @indices.delete(name) if not @indices[name].nil?
  
  @dbref.each_pair do |oldurid,v|
    next unless oldurid.match( self.record_prefix )
    old_record = Marshal.load( v )
    new_record = old_record.clone
    if oldspec[name] != newspec[name] then
      new_record[name] = self.convert_type( old_record[name], newspec[:datatype] )
    end
    newurid = self.get_hash_key( new_record )
    if newurid != oldurid then
      @dbref.delete(oldurid)
      @dbref[newurid] = Marshal.dump( new_record )
    else
      @dbref[oldurid] = Marshal.dump( new_record )
      #self.index_update( oldurid, newurid, new_record[name] )
    end
  end
  
  self.index_build( name ) if self.indexed?(name)
  
end

#comparison(value, operand, target) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 682

def comparison( value, operand, target ) #:nodoc:
  
  #puts "[#{value}] #{operand.to_s} [#{target}]"
  
  if operand.to_s == 'is' then
    return (value.to_s == target.to_s)
  elsif operand.to_s == 'not' then
    return (value.to_s != target.to_s)
  elsif operand.to_s == 'like' then
    target = '^' + target.gsub( /\%/, '.*' ) + '$'
    return (value.to_s.match( target ))
  elsif operand.to_s == 'unlike' then
    target = '^' + target.gsub( /\%/, '.*' ) + '$'
    return (not value.to_s.match( target ))
  elsif operand.to_s == 'under' then
    return (value.to_f < target.to_f)
  elsif operand.to_s == 'over' then
    return (value.to_f > target.to_f)
  elsif operand.to_s == 'before' then
    return (value.to_s < target.to_s)
  elsif operand.to_s == 'after' then
    return (value.to_s > target.to_s)
  elsif operand.to_s == 'between' then
    raise Trix51::TypeError, "BETWEEN clause requires two values" unless (target.class.name == 'Array') and (target.length > 1)
    s = target.sort
    lower_bound = s.shift
    upper_bound = s.pop
    return ( ( value.to_s >= lower_bound.to_s ) and ( value.to_s <= upper_bound.to_s ) )
  elsif operand.to_s == 'in' then
    raise Trix51::TypeError, "IN clause requires an array" unless (target.class.name == 'Array') and (target.length >= 1)
    return (target.include?( value ))
  end
  
end

#convert_type(value, typedef) ⇒ Object

Converts a value to the specified type.



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# File 'lib/trix51db.rb', line 1281

def convert_type( value, typedef )
  newvalue = nil
  if typedef == 'string' then
    return value.to_s
  end
  if typedef == 'integer' then
    return value.to_i
  end
  if typedef == 'float' then
    return value.to_f
  end
  if typedef == 'datetime' then
    return Time.parse(value.to_s).to_s
  end
end

#count ⇒ Object

Returns the number of records in the table or result set.



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# File 'lib/trix51db.rb', line 1358

def count
  return self.size
end

#create_index(fieldname) ⇒ Object

Creates an index on the specified field.

Raises:



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# File 'lib/trix51db.rb', line 1780

def create_index( fieldname )
  fieldname = fieldname
  raise Trix51::NotFoundError, "Table '#{self.tablename}' does not have a field '#{fieldname}'" unless self.exists?(fieldname)
  raise Trix51::ExistsError, "Table '#{self.tablename}' already has an index on field '#{fieldname}'" if self.indexed?(fieldname) 
  
  @meta = self.meta
  self.structure[fieldname][:indexed] = true
  self.meta = @meta
  
  self.index_build( fieldname )
end

#default(fieldname) ⇒ Object

Returns the default for the specified field.



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# File 'lib/trix51db.rb', line 596

def default( fieldname )
  
  unless self.exists?( fieldname) then
    raise Trix51::NotFoundError, "field not found: #{fieldname} in table #{@meta[:tablename]}"
  end
  
  ref = self.structure[fieldname]
  
  #pp ref
  
  if (ref[:autoincrement] == true) and (ref[:datatype] == 'integer') then
    return self.find_or_create_seq( fieldname )
  end
  
  if (not ref[:default].nil?) then
    d = ref[:default]
    if m = d.to_s.match( /^\#\{(.+)\}$/ ) then
      return eval(m[1])
    end
    return d
  end
  
  return nil
  
end

#delete(*args) ⇒ Object

Deletes records matching the query.

Example

count = animal.delete( species_id: 2 )



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# File 'lib/trix51db.rb', line 789

def delete( *args )
  return self.delete_hash( args_to_hash(*args) )
end

#delete_hash(hashdata) ⇒ Object

delete records matching the specified hash

Example

num_deleted = animal.delete_hash( {

name: ‘cow’

} )



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# File 'lib/trix51db.rb', line 736

def delete_hash( hashdata ) #:nodoc:
  
  matches = self.select_hash( hashdata )
   
  matches.each_record do |record|
	     urid = record.urid 
             @dbref.delete( urid )
	     self.index_remove( urid )
  end
  
  return matches.length
  
end

#distinct(*keylist) ⇒ Object

Returns a new result set containing a list of the unique values.



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# File 'lib/trix51db.rb', line 1643

def distinct( *keylist )
  
  structure = {}
  keylist.each do |key|
    key = key
    structure[key] = self.structure[key]
    structure[key][:key] = true
  end	 
  
  agg_records = {}
  
  self.each_record do |record|
    
    nurid =  self.group_key( record.data, keylist )
    next unless agg_records[nurid].nil?
    
    agg_records[nurid] = {}
    keylist.each do |key|
      key = key
      agg_records[nurid][key] = record.data[key]
    end
    
  end
  
  res = Trix51::ResultSet.new( 'aggregate_'+self.tablename, {}, { tableref: self, structure: structure } )
  meta_init = res.meta
  meta_init[:structure] = structure
  res.meta = meta_init
  
  agg_records.each_pair do |k,v|
    res.dbref[k] = Trix51::Tuple.new( self, k, v )
  end
  
  return res	  
end

#dump ⇒ Object

Produces a neatly formatted dump of the records (all fields)



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# File 'lib/trix51db.rb', line 1403

def dump
  fields = self.structure.keys
  self.dump_filtered( *fields )
end

#dump_filtered(*fieldnames) ⇒ Object

Produces a neatly formatted dump of the records (selected fields)



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# File 'lib/trix51db.rb', line 1409

def dump_filtered( *fieldnames )
  
  widths = {}
  #fieldnames = self.structure.keys.sort if fieldnames.length == 0
  lines = []
  
  tmp = []
  fieldnames.each do |fn|
    tmp.push( fn ) if self.exists?( fn )
  end
  fieldnames = tmp 
 
  fieldnames.each do |field|
    widths[field] = field.length+2
    
    str = ''
    (field.length+1).times do |n|
      str = str + '-'
    end
    
    lines.push( str )
  end
 
  @dbref.each_pair do |k, v|
    #pp v
    next unless self.table_record?(k)
    record = nil
    if self.table? then
      record = Marshal.load( v )
    else
      record = v.data
    end
    fieldnames.each do |field|
      fv = record[field] || 'nil'
      widths[field] = fv.to_s.length+2 if fv.to_s.length+2 > widths[field]
    end	    
  end
  
  # create formatstr
  formatstr = ''
  fieldnames.each do |field|
    formatstr = formatstr + " %-#{widths[field]}s|"
  end
  
  puts sprintf "#{formatstr}", *fieldnames
  puts sprintf "#{formatstr}", *lines
  
  self.each_record do |v|
    record = v.data
    values = []
    fieldnames.each do |field|
      values.push( record[field] || 'nil' )
    end	    
    puts sprintf "#{formatstr}", *values
  end
  
  #pp @dbref
  
end

#each ⇒ Object

Interate over records in the table or resultset. Any updates are automatically updated in the database.



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# File 'lib/trix51db.rb', line 1304

def each
  
  self.sorted_keys.each do |k|
    next unless k.match( Trix51::RECORD_PREFIX )
    r = init_record(k)
    yield record
    r.update if r.has_updates?
  end
  
end

#each_key ⇒ Object

Interates through each key in the dbm store.



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# File 'lib/trix51db.rb', line 1326

def each_key
  self.sorted_keys.each do |k|
    yield k if self.table_record?(k)
  end	  
end

#each_pair ⇒ Object

Iterates through each key, value for the table.



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# File 'lib/trix51db.rb', line 1316

def each_pair
  
  self.sorted_keys.each do |k|
    next unless self.table_record?(k)
    yield k, init_record(k) 
  end
  
end

#each_record ⇒ Object

Iterates through each Trix51::Tuple in the table or result set.



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# File 'lib/trix51db.rb', line 1343

def each_record
  self.sorted_keys.each do |k|
    next unless k.match( self.record_prefix )
    r = init_record(k)
    yield r
    r.update if r.has_updates?
  end	  
end

#each_value ⇒ Object

Interates through each Trix51::Tuple in the table or result set.



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# File 'lib/trix51db.rb', line 1333

def each_value
  self.sorted_keys.each do |k|
    next unless k.match( self.record_prefix )
    r = init_record(k)
    yield r
    r.update if r.has_updates?
  end	  
end

#empty ⇒ Object

Deletes all records in the table.



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# File 'lib/trix51db.rb', line 837

def empty
  return self.delete_hash( {} )
end

#empty_rec ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 924

def empty_rec #:nodoc:
  ref = {}
  self.structure.each_key { |key|
    ref[key] = self.default( key )
  }
  return ref
end

#eval_in_context(hashdata, expression) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 717

def eval_in_context( hashdata, expression ) #:nodoc:
  inits = []
  hashdata.each_pair do |k,v|
    next if v.nil?
    str = ''
    str = %Q|#{k} = #{v}|  if v.class.name != 'String'
    str = %Q{#{k} = %Q|#{v}|} if v.class.name == 'String'
    inits.push( str )
  end
  inits.push( expression )
  str = inits.join("\n")
  return eval( str )
end

#exists?(fieldname) ⇒ Boolean

Returns true / false if the table contains field

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 623

def exists?( fieldname )
  return (not self.structure[fieldname].nil?)
end

#find_or_create(*args) ⇒ Object

Find (select) or create a record with the named arguments.



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# File 'lib/trix51db.rb', line 987

def find_or_create( *args )  
  
  res = self.first( *args )
  
  if res.nil? then
    return self.insert_hash( args_to_hash(*args) )
  end
  
  return res
  
end

#find_or_create_seq(fieldname) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 627

def find_or_create_seq( fieldname ) #:nodoc:
  
  seq_name =self.seq_prefix( fieldname )
  #puts "Sequence is called: #{seq_name}"
  
  if @dbref[seq_name].nil? then
    @dbref[seq_name] = '2'
    return 1
  else
    v = @dbref[seq_name].to_i
    @dbref[seq_name] = (v+1).to_s
    return v
  end
  
end

#first(*args) ⇒ Object

Returns the first record matching the query (Trix51::Tuple)



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# File 'lib/trix51db.rb', line 821

def first( *args )
    res = self.select_hash( args_to_hash(*args) )
    if res.count > 0 then
      res.each_record do |x|
	return x
      end
      return nil
    end
end

#get_hash_key(hashdata) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 913

def get_hash_key( hashdata ) #:nodoc:
  keys = self.key_fields
  
  v = []
  keys.each { |k|
    v.push( hashdata[k] )
  }
  
  return self.record_prefix + ':' + v.join( Trix51::KEY_JOIN )
end

#group(*args) ⇒ Object

Groups records by the array of fields specified in the by: clause, and returns the aggregated results for the fields specified in the calculate: clause.

Group calculations

  • sum: - Sum of the field values

  • max: - Max of the field values

  • min: - Min of the field values

  • avg: - Average of the field values

  • count: - Count of the field values

Example

animal.group( by: [ :species_id ], calculate: { number_of_eyes: 'sum' } ).dump

species_id   |sum_number_of_eyes  |
-----------  |------------------- |
1            | 28                 |
2            | 40                 |



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# File 'lib/trix51db.rb', line 1537

def group( *args )
  params = args.shift
  #pp params
  keylist = params[:by]
  fields = params[:calculate]
  
  collected_data = {}
  structure = {}
  agg_records = {}
  
  keylist.each do |key|
    structure[key] = self.structure[key]
    structure[key][:key] = true
  end	  
  
  fields.each_pair do |field,function|
    new_field = function.to_s + '_' + field.to_s
    structure[new_field.to_sym] = { :datatype => 'string' }
  end
  
  self.each_record do |record|
    
    nurid =  self.group_key( record.data, keylist )
    
    agg_records[nurid] = {}
    keylist.each do |key|
      key = key
      agg_records[nurid][key] = record.data[key]
    end
   
    
    # for this record, aggregate 
    fields.each_key do |field|
      collected_data[nurid] = {} if collected_data[nurid].nil?
      collected_data[nurid][field] = [] if collected_data[nurid][field].nil?
      values = collected_data[nurid][field]
      if self.structure[field][:datatype] == 'calculated' then
	values.push( self.eval_in_context( record.data, self.structure[field][:calculation] ) )
      else
	values.push( record.data[field] )
      end
      collected_data[nurid][field] = values
    end
   
    
    # now collapse the data into hashes
    collected_data.each_key do |nurid|
      # by key, process each function
      
      # copy keylist fields in
      
      
      fields.each_pair do |field,function|
	field = field
	function = function
	new_field = (function.to_s + '_' + field.to_s).to_sym
	values = collected_data[nurid][field]
	
	if function == 'sum' then
	  agg_records[nurid][new_field] = values.reduce(:+)
	elsif function == 'avg' then
	  agg_records[nurid][new_field] = values.reduce(:+) / values.count
	elsif function == 'min' then
	  agg_records[nurid][new_field] = values.min
	elsif function == 'max' then
	  agg_records[nurid][new_field] = values.max
	elsif function == 'count' then
	  agg_records[nurid][new_field] = values.count			  
	else
	    raise Trix51::NotFoundError, "unknown group function #{function}"
	end
	
      end
      
    end
    
  end
  
  res = Trix51::ResultSet.new( 'aggregate_'+self.tablename, {}, { tableref: self, structure: structure } )
  meta_init = res.meta
  meta_init[:structure] = structure
  res.meta = meta_init

  agg_records.each_pair do |k,v|
    res.dbref[k] = Trix51::Tuple.new( self, k, v )
  end
  
  return res
  
end

#group_key(hashdata, keylist) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1507

def group_key( hashdata, keylist ) #:nodoc:
  keycode = []
  keylist.each do |key|
    if not hashdata[key].nil? then
      keycode.push( hashdata[key].to_s )
    else
      keycode.push( 'nil' )
    end
  end
  return Trix51::RECORD_PREFIX+'aggregate_'+self.tablename+':'+keycode.join(':')
end

#having(*args) ⇒ Object

Alias for select()



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# File 'lib/trix51db.rb', line 816

def having( *args )
  return self.select_hash( args_to_hash(*args) )
end

#hint_criteria_to_operand_target(criteria) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1738

def hint_criteria_to_operand_target( criteria ) #:nodoc:
  if criteria.class.name != 'Hash' then
    return [ 'is', criteria ]
  else
    operand = ''
    target = ''
    criteria.each_pair do |k, v|
      operand = k.to_s
      target = v
    end
    return [ operand, target ]
  end
end

#hint_matches_by_index(taglist, field, operand, target) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1698

def hint_matches_by_index( taglist, field, operand, target ) #:nodoc:
  newlist = []
  
  # match the criteria against each key in the index, collecting any matches if they are in the original
  # taglist
  
  self.index_build(field) if self.indices[field].nil?
  
  self.indices[field].each_pair do |fieldvalue, urid_list|
    if comparison( fieldvalue, operand, target ) then
      matches = urid_list & taglist
      newlist.push( *matches ) if matches.length > 0
    end
  end
  
  return newlist
end

#hint_matches_by_recordscan(taglist, field, operand, target) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1716

def hint_matches_by_recordscan( taglist, field, operand, target ) #:nodoc:
  
  newlist = []
  
  taglist.each do |urid|
    v = @dbref[urid]
    record = nil
    if v.class.name == 'String' then
      record = Marshal.load( v )
    else
      record = v.data
    end
    if self.structure[field][:datatype] == 'calculated' then
	record[field] = self.eval_in_context( record, self.structure[field][:calculation] )
    end
    newlist.push( urid ) if comparison( record[field], operand, target )
  end
  
  return newlist
  
end

#index_add(urid, record) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1035

def index_add( urid, record ) #:nodoc:
  record.keys.each { |fieldname|
    next unless self.indexed?(fieldname) 
    # check index exists
    if self.indices[fieldname].nil? then
	self.index_build( fieldname )
    else
	# partial add
	rv = record[fieldname]
	rlist = self.indices[fieldname][rv] || []
	rlist.push( urid )
	self.indices[fieldname][rv] = rlist
    end 
  }
end

#index_build(field) ⇒ Object

Rebuilds the index for the given field.



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# File 'lib/trix51db.rb', line 1018

def index_build( field )
  if not self.indexed?(field) then
    raise Trix51::NotFoundError, "field #{field} is not an indexed field"
  end
  #puts "Building index for field #{field}"
  res = {}
  self.dbref.each_pair { |k, v|
    next unless self.table_record?( k )
    record = Marshal.load( v )
    rv = record[field]
    rlist = res[rv] || []
    rlist.push( k )
    res[rv] = rlist
  }
  @indices[field] = res
end

#index_chk_unique(fieldname, fieldvalue) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1073

def index_chk_unique( fieldname, fieldvalue )#:nodoc:
  
  #puts fieldname + '=' + fieldvalue.to_s
  
  if self.indexed?( fieldname ) == false then
    return true
  end
  
  if self.unique?( fieldname) == false then
    return true
  end
  
  if fieldvalue.nil? then
      return false
  end
  
  if self.indices[fieldname].nil? then
    self.index_build( fieldname )
  end
  
  if self.indices[fieldname][fieldvalue].nil? then
    return true
  end
  
  if self.indices[fieldname][fieldvalue].length == 0 then
    return true
  end	  
  
  return false
end

#index_chk_unique_update(fieldname, fieldvalue, urid) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1104

def index_chk_unique_update( fieldname, fieldvalue, urid ) #:nodoc:
  
  #puts fieldname + '=' + fieldvalue.to_s
  
  if self.indexed?( fieldname ) == false then
    return true
  end
  
  if self.unique?( fieldname) == false then
    return true
  end
  
  if fieldvalue.nil? then
      return false
  end
  
  if self.indices[fieldname].nil? then
    self.index_build( fieldname )
  end
  
  if self.indices[fieldname][fieldvalue].nil? then
    return true
  end
  
  if self.indices[fieldname][fieldvalue].length == 0 then
    return true
  end	
  
  if (self.indices[fieldname][fieldvalue].length == 1) and (self.indices[fieldname][fieldvalue][0] == urid) then
    return true
  end
  
  return false
end

#index_remove(urid) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1065

def index_remove( urid ) #:nodoc:
  self.indices.each_pair { |fieldname, index|
      index.each_value { |rlist|
          rlist.delete( urid )
      }
  }
end

#index_update(oldurid, newurid, record) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1051

def index_update( oldurid, newurid, record ) #:nodoc:
  record.keys.each { |fieldname|
    next unless self.indexed?(fieldname)
    # check index exists
    if self.indices[fieldname].nil? then
	self.index_build( fieldname )
    else
	# partial update
	self.index_remove( oldurid )
	self.index_add( newurid, record )              
    end    
  }
end

#indexed?(field) ⇒ Boolean

returns true or false if a table field is indexed.

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 1000

def indexed?( field )
  return false unless self.exists?( field )
  return ( (self.key?(field)) or (self.unique?(field)) or ( (not self.structure[field][:indexed].nil?) and (self.structure[field][:indexed] == true) ) )
end

#indices_load(path) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1800

def indices_load( path ) #:nodoc:
  filename = path+'/'+self.tablename.to_s+'.idx'
  
  if File.exists?( filename ) then
    #puts "*** Load index: #{filename}"
    File.open( filename, 'r' ) do |file|
      self.indices = Marshal.load( file )
    end
  else
    #puts "*** Generating index for #{self.tablename}"
    self.structure.keys.each { |field|
      self.index_build( field ) if self.indexed?(field)
    }
  end
  #pp self.indices
end

#indices_save(path) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1792

def indices_save( path ) #:nodoc:
  filename = path+'/'+self.tablename.to_s+'.idx'
  #puts "*** Save index: #{filename}"
  File.open( filename, 'w' ) do |file|
    Marshal.dump( self.indices, file )
  end
end

#init_record(urid) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 874

def init_record( urid )  #:nodoc:
  
  #pp self.table?
  #pp @classname
  
  unless self.table? then
    return @dbref[ urid ]
  end
  
  r = nil
  if (@classname == 'Trix51::Tuple') or (Trix51.defer_classref == true) then
    r = Trix51::Tuple.new( self, urid )
  else
    r = eval( "#{@classname}.new( self, urid )" )
  end
  return r
end

#insert(*args) ⇒ Object

Inserts a record into the database using named arguments.



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# File 'lib/trix51db.rb', line 842

def insert( *args )
  return self.insert_hash( args_to_hash(*args) )
end

#insert_hash(hashdata) ⇒ Object

insert record into the database using a hash

Example

  daisy = animal.insert_hash( {
      name: 'cow',
species_id: 2
  } )

Raises:



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# File 'lib/trix51db.rb', line 649

def insert_hash( hashdata ) #:nodoc:
  
  ref = self.empty_rec.merge( hashdata ) { |key, oldval, newval|
    (not newval.nil?) ? newval : oldval
  }
  
  #pp ref
  
  flt = {}
  
  ref.each_key { |key|
    flt[key] = ref[key] if self.exists?( key )
  }
  
  #pp flt
  
  self.check_required_fields( flt )
  
  urid = self.get_hash_key( flt )
  
  #puts "Record key: #{urid}"
  
  raise Trix51::ConstraintError, "unique constraint has been violated (#{urid})" if @dbref[urid]
  
  @dbref[urid] = Marshal.dump( flt )
  
  #puts "INSERT "+@dbref[urid]
  
  self.index_add( urid, flt )
  
  return self.init_record( urid )
end

#key?(field) ⇒ Boolean

returns true or false if a table field forms part of the record key

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 1012

def key?( field )
  return false unless self.exists?( field )
  return ( (not self.structure[field][:key].nil?) and (self.structure[field][:key] == true) )
end

#key_fields ⇒ Object

Returns the key fields for the table



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# File 'lib/trix51db.rb', line 904

def key_fields 
  res = []
  self.structure.keys.sort.each { |key|
    #puts key
    res.push(key) if self.structure[key][:key] == true
  }
  return res
end

#length ⇒ Object

Returns the number of records in the table or result set.



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# File 'lib/trix51db.rb', line 1363

def length
  return self.size
end

#limit(count) ⇒ Object

Returns a new result set contain only the first count records.

Example

animal.select( number_of_legs: 4 ).sort( :name ).limit(2).dump_filtered( :name )

name      |
-----     |
aardvark  |
bullock   |



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# File 'lib/trix51db.rb', line 1687

def limit( count )
  res = Trix51::ResultSet.new( self.tablename, {}, { tableref: self } )
  done = 0
  self.each_record do |record|
    res.dbref[ record.urid ] = record if done < count
    done = done + 1
  end
  return res
end

#meta ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1391

def meta #:nodoc:
  if @meta.nil? then
    @meta = Marshal.load( @dbref[self.meta_prefix] )
  end
  return @meta
end

#meta=(meta) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1398

def meta=(meta) #:nodoc:
  @dbref[self.meta_prefix ] = Marshal.dump( meta )
end

#meta_prefix ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1383

def meta_prefix #:nodoc:
  return Trix51::META_PREFIX+self.tablename.to_s
end

#meta_record?(key) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 1375

def meta_record?( key ) #:nodoc:
  return (key.match(Trix51::META_PREFIX))
end

#push(record) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1352

def push( record ) #:nodoc:
  #puts "pushing record with urid = #{record.urid}"
  @dbref[ record.urid ] = record
end

#random ⇒ Object

Returns a random record from the table or result set.



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# File 'lib/trix51db.rb', line 1470

def random
  
  keys = []
  @dbref.each_key do |k|
    keys.push( k ) if self.table_record?(k)
  end
  
  return nil if keys.count == 0
  
  urid = keys[ rand( keys.count ) ]
  
  return init_record( urid )
  
end

#record_keys ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 570

def record_keys #:nodoc:
  list = []
  @dbref.each_key do |k|
    list.push( k ) if self.table_record?(k)
  end
  return list
end

#record_prefix ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1367

def record_prefix #:nodoc:
  return Trix51::RECORD_PREFIX+self.tablename.to_s
end

#select(*args) ⇒ Object

Returns a Trix51::ResultSet containing records matching the query.

Example

   records = animal.select(
name: { like: 'mon%' },
created_date: { between: [ '2012-04-11', 2012-12-31' ],
number_of_eyes: 2,
      number_of_legs: { in: [2,4] }
   )

Query operands

  • is: - true if value matches

  • in: - true if value is in specified list

  • not: - true if value does not match

  • under: - true if value is less than

  • over: - true if value is greater than

  • like: - true if value matches pattern ( ‘%’ acts as wildcard )

  • unlike: - true if value does not match pattern ( ‘%’ acts as wildcard )

  • between: - true if value is between specified values



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# File 'lib/trix51db.rb', line 811

def select( *args )
  return self.select_hash( args_to_hash(*args) )
end

#select_hash(criteria) ⇒ Object

Return records based on the specified query.



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# File 'lib/trix51db.rb', line 1753

def select_hash( criteria ) #:nodoc:
  #criteria = self.args_to_hash( *args )
  taglist = self.record_keys
  
  criteria.each_pair do |field, value|
    break if taglist.length == 0
    
    if self.indexed?(field) then
      #puts "#{field} will use index"
      taglist = self.hint_matches_by_index( taglist, field, *hint_criteria_to_operand_target(value) )
    else
      #puts "#{field} will use record level scan (less efficient)"
      taglist = self.hint_matches_by_recordscan( taglist, field, *hint_criteria_to_operand_target(value) )
    end
    
  end
  
  res = Trix51::ResultSet.new( self.tablename, {}, { tableref: self } )
  taglist.each do |key|
    res.push( self.init_record( key ) )
  end
  
  return res
  
end

#seq_prefix(fieldname) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 1387

def seq_prefix( fieldname ) #:nodoc:
  return Trix51::SEQ_PREFIX+self.tablename.to_s+'_'+fieldname.to_s+'_seq'
end

#seq_record?(key) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 1379

def seq_record?( key ) #:nodoc:
  return (key.match(Trix51::SEQ_PREFIX))
end

#size ⇒ Object

Returns the number of records in the database.



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# File 'lib/trix51db.rb', line 579

def size
      c = 0
      @dbref.each_key do |k|
	c = c + 1 if k.match( self.record_prefix )
      end
      return c
end

#sort(field, dir = 'asc') ⇒ Object

Sorts records by specified field and ordering, returning a new result set. Special symbol :random returns records in a randomized ordering.

Example

animal.select( number_of_legs: 4 ).sort( :name ).dump_filtered( :name )

name      |
-----     |
aardvark  |
bullock   |
cow       |



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# File 'lib/trix51db.rb', line 1495

def sort( field, dir='asc' )
  
  res = Trix51::ResultSet.new( self.tablename, {}, { tableref: self, sorted:  true, sortfield: field, sortorder: dir } )
  
  self.each_key do |k|
    res.push( init_record( k ) )
  end
  
  return res
  
end

#sorted_keys ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 559

def sorted_keys #:nodoc:
  if (not @options[:sorted].nil?) and (@options[:sorted] == true) then
    #return self.build_sorted_keys( @options['sortfield'].to_s, @options['sortorder'] )
    if @sort_order.nil? then
      @sort_order = self.build_sorted_keys( @options[:sortfield], @options[:sortorder] )
    end
    return @sort_order
  end
  return @dbref.keys
end

#structure ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 591

def structure #:nodoc:
  return @meta[:structure]
end

#table? ⇒ Boolean

Returns true if the given object is a table, false otherwise

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 1298

def table? 
  return (@dbref.class.name == 'GDBM')
end

#table_record?(key) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 1371

def table_record?( key ) #:nodoc:
  return (key.match(self.record_prefix))
end

#tuple_by_key(*args) ⇒ Object

:nodoc:



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# File 'lib/trix51db.rb', line 857

def tuple_by_key( *args ) #:nodoc:
  keys = self.key_fields
  h = {}
  keys.each { |key|
    h[key] = args.shift
  }
  #pp h
  urid = self.get_hash_key( h )
  
  s = dbref[urid]
  
  return Marshal.load( s ) if self.table? and not s.nil?
  return s if not s.nil?
  
  return nil
end

#unique?(field) ⇒ Boolean

returns true or false if a table field must be unique

Returns:

  • (Boolean) 


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# File 'lib/trix51db.rb', line 1006

def unique?( field )
  return false unless self.exists?( field )
  return ( (not self.structure[field][:unique].nil?) and (self.structure[field][:unique] == true) )
end

#update(*args) ⇒ Object

Updates records matching the query.

Example

animal.update( number_of_eyes: 2, number_of_legs: 4 ) do |record|

record.number_of_eyes = 8

end



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# File 'lib/trix51db.rb', line 772

def update( *args )

    hashdata = args_to_hash( *args )
  
    matches = self.select_hash( hashdata )
    
    matches.each { |record|
      yield record
      record.update if record.has_updates?
    }
  
    return matches.length
end

#update_hash(hashdata) ⇒ Object

Updates any records matching the values in hash

Example

animal.update_hash ( { name: 'cow' } ) do |record|

record.name = ‘sheep’ # baaa?

end



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# File 'lib/trix51db.rb', line 755

def update_hash( hashdata ) #:nodoc:
 
    matches = self.select_hash( hashdata )
    
    matches.each { |record|
      yield record
      record.update if record.has_updates?
    }
  
    return matches.length
end