Class: Arcade::Query

Inherits:
Object
  • Object
show all
Includes:
Support::Model, Support::Sql
Defined in:
lib/init.rb,
lib/query.rb

Overview

Provides method ‘db` to every Query-Object

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Support::Model

#_allocate_model, #resolve_edge_name

Methods included from Support::Sql

#compose_where, #generate_sql_list

Constructor Details

#initialize(**args) ⇒ Query

Returns a new instance of Query.



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# File 'lib/query.rb', line 17

def initialize  **args
	@q =  QueryAttributes.new args[:kind] ||	'select' ,
						[], #		 :projection 
						[], # :where ,
						[], # :let ,
						[], # :order,
						[], # :while,
						[] , # misc
						'',  # class
						'',  #  return
						[],   # aliases
						'',  # database
						[],   #set,
						[]  # remove
	  args.each{|k,v| send k, v}
		@fill = block_given? ?   yield  : 'and'
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *arg, &b) ⇒ Object

where: “r > 9” –> where r > 9

where: {a: 9, b: 's'}                   --> where a = 9 and b = 's'
where:[{ a: 2} , 'b > 3',{ c: 'ufz' }]  --> where a = 2 and b > 3 and c = 'ufz'



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# File 'lib/query.rb', line 40

def method_missing method, *arg, &b   # :nodoc:
			if method ==:while || method=='while'
while_s arg.first
			else
@q[:misc] << method.to_s <<  generate_sql_list(arg)
			end
			self
end

Class Method Details

.mk_simple_setter(*m) ⇒ Object 



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# File 'lib/query.rb', line 172

def mk_simple_setter *m
	m.each do |def_m|
		define_method( def_m ) do | value=nil |
				if value.present?
					@q[def_m]  = value
					self
				elsif @q[def_m].present?
				 "#{def_m.to_s} #{generate_sql_list(@q[def_m]){' ,'}}"
				end
		end
	end
end

.mk_std_setter(*m) ⇒ Object 



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# File 'lib/query.rb', line 184

def mk_std_setter *m
	m.each do |def_m|
		define_method( def_m  ) do | value = nil |
			if value.present?
				@q[def_m] << case value
											when String
												value
											when ::Hash
												value.map{|k,v| "#{k} = #{v.to_or}"}.join(", ")
											else
												raise "Only String or Hash allowed in  #{def_m} statement"
											end
				self
			elsif @q[def_m].present?
				"#{def_m.to_s} #{@q[def_m].join(',')}"
			end # branch
		end     # def_method
	end  # each
end

Instance Method Details

#as(a = nil) ⇒ Object 



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# File 'lib/query.rb', line 228

def as a=nil
  if a
    @q[:as] = a   # subsequent calls overwrite previous entries
  else
    if @q[:as].blank?
      nil
    else
      "as: #{ @q[:as] }"
    end
  end
end

#compose(destination: :batch) ⇒ Object Also known as: to_s

Output the compiled query

Parameter: destination (rest, batch )
If the query is submitted via the REST-Interface (as get-command), the limit parameter is extracted.



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# File 'lib/query.rb', line 71

def compose(destination: :batch)
	if kind.to_sym == :update
		return_statement = "return after " + ( @q[:aliases].empty? ?  "$current" : @q[:aliases].first.to_s)
		[ 'update', target, set, remove, return_statement, where ].compact.join(' ')
    elsif kind.to_sym == :"update_map"
      [ "update", target, map, where, misc ].compact.join(' ')
	elsif kind.to_sym == :update!
		[ 'update', target, set, where, misc ].compact.join(' ')
#			elsif kind.to_sym == :create                                             # relict of orientdb
#				[ "CREATE VERTEX", target, set ].compact.join(' ')
	#	[ kind, target, set,  return_statement ,where,  limit, misc ].compact.join(' ')
	elsif kind.to_sym == :upsert
      set(  generate_sql_list( @q[:where] ){ @fill || 'and' } ) if set.nil?
		return_statement = "return after " + ( @q[:aliases].empty? ?  "$current" : @q[:aliases].first.to_s)
		[ "update", target, set,"upsert", return_statement, where, limit, misc  ].compact.join(' ')
		#[ kind,  where, return_statement ].compact.join(' ')
	elsif destination == :rest
		[ kind, projection, from, let, where, subquery,  misc, order, group_by, unwind, skip].compact.join(' ')
	else
		[ kind, projection, from, let, where, subquery,  while_s,  misc, order, group_by, limit, unwind, skip].compact.join(' ')
	end
end

#connect_with(in_or_out, via: nil) ⇒ Object

connects by adding in_or_out(‘edgeClass’)



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# File 'lib/query.rb', line 315

def connect_with in_or_out, via: nil
	 argument = " #{in_or_out}(#{via.to_or if via.present?})"
end

#database_class ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 158

def database_class            # :nodoc:
  @q[:database]
end

#database_class=(arg) ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 162

def database_class= arg   # :nodoc:
  @q[:database] = arg
end

#db ⇒ Object 



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# File 'lib/init.rb', line 45

def db
  Init.db
end

#distinct(d) ⇒ Object 



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# File 'lib/query.rb', line 166

def distinct d
	@q[:projection] << "distinct " +  generate_sql_list( d ){ ' as ' }
	self
end

#execute(reduce: false, autoload: true) ⇒ Object

returns nil if the query was not sucessfully executed



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# File 'lib/query.rb', line 350

def execute(reduce: false, autoload: true )
#      unless projection.nil?    || projection.empty?
    result = db.execute { compose }
	return nil unless result.is_a?(Array)
	block_given?  ? result.map{|x| yield x }  : result
#			return  result.first if reduce && result.size == 1
    ## case  select count(*) from  ...  --> [{ :count => n }]   projection is set
    ## case update ... after $current   --> [{ :$current => n}] projection is not set, but result is an integer
    #  separate key from  values and get model-files
#      if  !@q[:projection].empty?  && result.first.is_a?(Hash)  &&  result.first.values.is_a?( Array ) 
#        if reduce
#          result.first.values.map{|x| allocate_model x, autoload}
#        else
#          result.map{|_,m| allocate_model m, autoload }
#        end
#     eloe
 #      result.map{|y| allocate_model y, autoload }
 #     end
	## standard case: return Array
	#result.arcade_flatten
end

#expand(item) ⇒ Object 



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# File 'lib/query.rb', line 309

def expand item
			@q[:projection] =[ " expand ( #{item.to_s} )" ]
			self
end

#from(arg = nil) ⇒ Object

from can either be a Databaseclass to operate on or a Subquery providing data to query further



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# File 'lib/query.rb', line 128

def from arg = nil
	if arg.present?
		@q[:database] =  arg
		self # return query-object
	elsif  @q[:database].present? # read from
		"from #{ target }"
	end
end

#get_limit ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 305

def get_limit  # :nodoc:
  @q[:limit].nil? ? -1 : @q[:limit].to_i
end

#group(value = nil) ⇒ Object Also known as: group_by 



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# File 'lib/query.rb', line 293

def group value = nil
			if value.present?
    @q[:group] << value
			self
  elsif @q[:group].present?
    "group by #{@q[:group].join(', ')}"
			end
end

#kind(value = nil) ⇒ Object 



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# File 'lib/query.rb', line 57

def kind value=nil
	if value.present?
		@q[:kind] = value
		self
	else
	@q[:kind]
	end
end

#let(value = nil) ⇒ Object 



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# File 'lib/query.rb', line 250

def let       value = nil
  if value.present?
    @q[:let] << value
    self
  elsif @q[:let].present?
    "let " << @q[:let].map do |s|
      case s
      when String
        s
      when ::Hash
        s.map do |x,y|
          # if the symbol: value notation of Hash is used, add "$" to the key
          x =  "$#{x.to_s}"  unless x.is_a?(String) && x[0] == "$"
          "#{x} = #{ case y
          when self.class
            "(#{y.compose})"
          else
            y.to_db
          end }"
        end
      end
    end.join(', ')
  end
end

#map(value = nil) ⇒ Object

update_map - update an embedded map



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# File 'lib/query.rb', line 241

def map  value=nil
   if value.present?
     @q[:map] = value
     self
   elsif @q[:map].present?
     # only one pair is supported
     "set #{@q[:map].keys.first} = #{@q[:map].values.first.to_or}"
   end
end

#misc ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 49

def misc   # :nodoc:
	@q[:misc].join(' ') unless @q[:misc].empty?
end

#nodes(in_or_out = :out, via: nil, where: nil, expand: false) ⇒ Object

adds a connection

in_or_out:  :out --->  outE('edgeClass').in[where-condition]
            :in  --->  inE('edgeClass').out[where-condition]



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# File 'lib/query.rb', line 322

def nodes in_or_out = :out, via: nil, where: nil, expand:  false

	 condition = where.present? ?  "[ #{generate_sql_list(where)} ]" : ""
     via = resolve_edge_name(via) unless via.nil?

     start =  if in_or_out.is_a? Symbol
                in_or_out.to_s
              elsif in_or_out.is_a? String
                in_or_out
						else
							"both"
						end
	 argument = " #{start}(#{via})#{condition} "

	 if expand.present?
		 send :expand, argument
	 else
		 @q[:projection]  << argument
	 end
	 self
end

#order(value = nil) ⇒ Object Also known as: order_by 



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# File 'lib/query.rb', line 138

def order  value = nil
	if value.present?
		@q[:order] << value
		self
	elsif @q[:order].present?

		"order by " << @q[:order].compact.flatten.map do |o|
			case o
			when String, Symbol, Array
				o.to_s
			else
				o.map{|x,y| "#{x} #{y}"}.join(" ")
			end  # case
		end.join(', ')
	else
		''
	end # unless
end

#projection(value = nil) ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 275

def projection value= nil  # :nodoc:
	if value.present?
		@q[:projection] << value
		self
	elsif  @q[:projection].present?
		@q[:projection].compact.map do | s |
			case s
			when ::Array
				s.join(', ')
			when String, Symbol
				s.to_s
			when ::Hash
				s.map{ |x,y| "#{x} as #{y}"}.join( ', ')
			end
		end.join( ', ' )
	end
end

#query ⇒ Object 



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# File 'lib/query.rb', line 345

def query
   db.query compose
end

#resolve_target ⇒ Object 



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

def resolve_target
	if @q[:database].is_a? Query
		@q[:database].resolve_target
	else
		@q[:database]
	end
end

#subquery ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 53

def subquery  # :nodoc:
  nil
end

#target(arg = nil) ⇒ Object 



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# File 'lib/query.rb', line 100

def target arg =  nil
	if arg.present?
		@q[:database] =  arg
		self # return query-object
	elsif @q[:database].present?
		the_argument =  @q[:database]
		case @q[:database]
							when Base   # a single record
								the_argument.rid
							when self.class	      # result of a query
								' ( '+ the_argument.compose + ' ) '
							when Class
								the_argument.database_name
							else
								if the_argument.to_s.rid?	  # a string with "#ab:cd"
									the_argument
								else		  # a database-class-name
									the_argument.to_s
								end
							end
	else
		raise "cannot complete until a target is specified"
	end
end

#to_or ⇒ Object 



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# File 'lib/query.rb', line 96

def to_or
	compose.to_or
end

#where(value = nil) ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 215

def where  value=nil     # :nodoc:
  if value.present?
    if value.is_a?( Hash ) && value.size >1
      value.each {| a, b | where( {a => b} ) }
    else
      @q[:where] <<  value
    end
    self
  elsif @q[:where].present?
    "where #{ generate_sql_list( @q[:where] ){ @fill || 'and' } }"
  end
end

#while_s(value = nil) ⇒ Object

:nodoc:



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# File 'lib/query.rb', line 207

def while_s  value=nil     # :nodoc:
  if value.present?
    @q[:while] << value
    self
  elsif @q[:while].present?
    "while #{ generate_sql_list( @q[:while] ) }"
  end
end