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−# This Source Code Form is subject to the terms of the Mozilla Public
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−# License, v. 2.0.  If a copy of the MPL was not distributed with this
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−# file, You can obtain one at http://mozilla.org/MPL/2.0/.
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−#
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−# Copyright 1997 - July 2008 CWI, August 2008 - 2017 MonetDB B.V.
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−
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−# Models a MonetDB RecordSet
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−require 'time'
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−require 'date'
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−require 'ostruct'
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−
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−require "bigdecimal"
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−
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−require_relative 'MonetDBConnection'
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−
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−require 'logger'
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−
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−class MonetDBData 
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−  @@DEBUG               = false
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− 
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−  def initialize(connection)
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−    @connection = connection
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−    @lang = @connection.lang
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−
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−    # Structure containing the header+results set for a fired Q_TABLE query     
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−    @header = []
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−    @query  = {}
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−    
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−    @record_set = []
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−    @index = 0 # Position of the last returned record
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−    
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−    
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−    @row_count = 0
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−    @row_offset = 10
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−    @row_index = Integer(MonetDBConnection::REPLY_SIZE)
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−  end
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−  
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−  # Fire a query and return the server response
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−  def execute(q)
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−   # fire a query and get ready to receive the data      
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−    @connection.send(format_query(q))
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−    data = @connection.receive
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−    
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−    return if data == nil
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−    
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−    record_set = "" # temporarly store retrieved rows
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−    record_set = receive_record_set(data)
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−
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−    if (@lang == MonetDBConnection::LANG_SQL)
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−      rows = receive_record_set(data)
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−      # the fired query is a SELECT; store and return the whole record set
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−      if @action == MonetDBConnection::Q_TABLE
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−        @header = parse_header_table(@header)
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−        @header.freeze
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−      
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−        if @row_index.to_i < @row_count.to_i
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−          block_rows = ""
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−          while next_block
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−            data = @connection.receive
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−            block_rows += receive_record_set(data)
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−          end
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−          record_set += block_rows
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−        end
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−      end
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−
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−      # ruby string management seems to not properly understand the MSG_PROMPT escape character.
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−      # In order to avoid data loss the @record_set array is built once that all tuples have been retrieved
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−      @record_set = record_set.split("\t]\n")
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−      
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−      if @record_set.length != @query['rows'].to_i
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−        raise MonetDBQueryError, "Warning: Query #{@query['id']} declared to result in #{@query['rows']} but #{@record_set.length} returned instead"
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−      end
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−    end
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−    @record_set.freeze  
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−  end
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−  
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−  # Returns the record set entries hashed by column name orderd by column position
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−  def fetch_all_as_column_hash
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−     columns = {}
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−     @header["columns_name"].each do |col_name|
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−       columns[col_name] = fetch_by_column_name(col_name)
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−     end
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−
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−     return columns
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−   end
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−
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−  # returns a record hash (i.e: { id: 1, name: "John Doe", age: 42 } )
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−  def fetch_hash
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−    return false if @index >= @query['rows'].to_i 
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−
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−    record_hash = record_hash(parse_tuple(@record_set[@index]))
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−    @index += 1
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−    return record_hash
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−  end
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−
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−  # loops through all the hashes of the records and yields them to a given block
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−  def each_record_as_hash
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−    @record_set.each do |record| 
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−      parsed_record = parse_tuple(record)
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−      yield(record_hash(parsed_record))
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−    end
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−  end
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−
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−  # Returns the values for the column 'field'
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−  def fetch_by_column_name(column_name="")
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−    position = @header["columns_order"].fetch(column_name)
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−
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−    column_values = []
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−    @record_set.each do |row|
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−      column_values << parse_tuple(row)[position]
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−    end
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−
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−    return column_values
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−  end
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−
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−  # fetches a single record, updates the iterator index
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−  def fetch
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−    return false if @index >= @query['rows'].to_i
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−
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−    result = parse_tuple(@record_set[@index])
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−    @index += 1
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−
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−    return result
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−  end
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−
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−  # resets the internal iterator index used by fetch and fetch_hash
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−  def reset_index
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−    @index = 0
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−  end
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−
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−  # loops through all records and yields to a given block paramter
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−  def each_record
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−    raise MonetDBDataError, "There is no record set currently available" unless @query['type'] == MonetDBConnection::Q_TABLE 
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−    @record_set.each { |record| yield(parse_tuple(record)) }
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−  end
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−
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−  # Cursor method that returns all the records
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−  def fetch_all
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−    result = []
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−    each_record do |record|
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−      result.push(record)
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−    end
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−    return result
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−  end
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−  
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−  # Returns the number of rows in the record set
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−  def num_rows
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−      return @query['rows'].to_i
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−   end
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−
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−  # Returns the number of fields in the record set
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−  def num_fields
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−     return @query['columns'].to_i
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−   end
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−
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−  # Returns the (ordered) name of the columns in the record set
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−  def name_fields
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−    return @header['columns_name']
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−  end
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−  
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−  # Returns the (ordered) name of the columns in the record set
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−  def type_fields
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−    return @header['columns_type']
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−  end
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−  
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−  # ===================
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−          private
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−  # ===================
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−  
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−  # store block of data, parse it and store it.
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−  def receive_record_set(response)
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−    rows = ""
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−    response.each_line do |row|
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−      case row[0]
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−      when MonetDBConnection::MSG_QUERY then parse_query(row)
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−      when MonetDBConnection::MSG_INFO then raise MonetDBQueryError, row
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−      when MonetDBConnection::MSG_SCHEMA_HEADER then @header << row
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−      when MonetDBConnection::MSG_TUPLE then rows += row
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−      when MonetDBConnection::MSG_PROMPT then return rows
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−      end
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−    end
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−    return rows # return an array of unparsed tuples
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−  end
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−
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−  def parse_query(row)
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−    case row[1]
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−      when MonetDBConnection::Q_TABLE
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−        @action = MonetDBConnection::Q_TABLE
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−        @query = parse_header_query(row)
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−        @query.freeze
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−        @row_count = @query['rows'].to_i #total number of rows in table        
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−      when MonetDBConnection::Q_BLOCK
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−        @action = MonetDBConnection::Q_BLOCK # strip the block header from data
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−        @block = parse_header_query(row)     
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−      when MonetDBConnection::Q_TRANSACTION
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−        @action = MonetDBConnection::Q_TRANSACTION
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−      when MonetDBConnection::Q_CREATE
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−        @action = MonetDBConnection::Q_CREATE
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−    end
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−  end
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−  
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−  def record_hash(record)
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−    result = {}
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−
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−    @header["columns_name"].each do |column_name|
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−       position = @header["columns_order"].fetch(column_name)
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−       result[column_name] = record[position]
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−     end
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−
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−    return result
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−  end
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−
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−  def next_block
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−    if @row_index == @row_count
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−      return false
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−    else
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−      # The increment step is small to better deal with ruby socket's performance.
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−      # For larger values of the step performance drop;
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−      #
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−      @row_offset = [@row_offset, (@row_count - @row_index)].min
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−      
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−      # export offset amount
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−      @connection.set_export(@query['id'], @row_index.to_s, @row_offset.to_s)    
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−      @row_index += @row_offset    
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−      @row_offset += 1
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−    end    
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−      return true
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−      
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−  end
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−  
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−  # Formats a query <i>string</i> so that it can be parsed by the server
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−  def format_query(q)
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−    if @lang == MonetDBConnection::LANG_SQL
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−        return "s" + q + "\n;"
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−    else
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−      raise LanguageNotSupported, @lang
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−    end
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−  end
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−  
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−  # parse one tuple as returned from the server
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−  def parse_tuple(tuple)
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−    fields = []
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−    # remove trailing  "["
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−    tuple = tuple.gsub(/^\[\s+/,'')
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−    tuple.split(/,\t/).each_with_index do |field, index|
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−      field_value = convert_type(field, index)
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−      fields << field_value
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−    end
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−    
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−    return fields.freeze
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−  end
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−
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−  # converts the given value the correct type
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−  def convert_type(value, index)
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−    return nil if "NULL" == value.upcase
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−    return case type_fields.values[index]
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−        when "int", "tinyint", "smallint", "bigint", "hugeint" then value.to_i
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−        when "double", "real", "decimal" then value.to_f
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−        when "boolean" then value.downcase == true
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−        when "date" then Date.parse(value)
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−        when "time" then Time.parse(value, Time.new("2000-01-01"))
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−        when "timestamp" then DateTime.parse(value)
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−        when "timestamptz" then DateTime.parse(value)
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−        else value.gsub(/\\/, '').gsub(/^"/,'').gsub(/"$/,'').gsub(/\"/, '')
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−      end
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−  end
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−  
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−  # Parses a query header and returns information about the query.
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−  def parse_header_query(row)
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−    type = row[1].chr
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−    if type == MonetDBConnection::Q_TABLE
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−      # Performing a SELECT: store informations about the table size, query id, total number of records and returned.
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−      id = row.split(' ')[1]
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−      rows = row.split(' ')[2]
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−      columns = row.split(' ')[3]
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−      returned = row.split(' ')[4]
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−      
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−      header = { "id" => id, "type" => type, "rows" => rows, "columns" => columns, "returned" => returned }
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−    elsif  type == MonetDBConnection::Q_BLOCK
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−      # processing block header
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−    
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−      id = row.split(' ')[1]
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−      columns = row.split(' ')[2]
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−      remains = row.split(' ')[3]
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−      offset = row.split(' ')[4]
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−      
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−      header = { "id" => id, "type" => type, "remains" => remains, "columns" => columns, "offset" => offset }
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−    else
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−      header = {"type" => type}
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−    end
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−    
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−    return header.freeze
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−  end
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−  
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−  # Parses a Q_TABLE header and returns information about the schema.
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−  def parse_header_table(header_t)
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−    if @query["type"] == MonetDBConnection::Q_TABLE
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−      if header_t != nil
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−        name_t = header_t[0].split(' ')[1].gsub(/,$/, '')
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−        name_cols = Array.new
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−      
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−        header_t[1].split('%')[1].gsub(/'^\%'/, '').split('#')[0].split(' ').each do |col|
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−          name_cols << col.gsub(/,$/, '')
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−        end
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−      
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−        type_cols = { }
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−        header_t[2].split('%')[1].gsub(/'^\%'/, '').split('#')[0].split(' ').each_with_index do |col, i|
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−          if  col.gsub(/,$/, '') != nil
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−            type_cols[ name_cols[i] ] = col.gsub(/,$/, '') 
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−          end
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−        end
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−      
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−        length_cols = { }
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−        header_t[3].split('%')[1].gsub(/'^\%'/, '').split('#')[0].split(' ').each_with_index do |col, i|
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−          length_cols[ name_cols[i] ] = col.gsub(/,$/, '')
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−        end
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−      
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−        columns_order = {}
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−        name_cols.each_with_index do |col, i|
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−          columns_order[col] = i
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−        end
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−      
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−        return {"table_name" => name_t, "columns_name" => name_cols, "columns_type" => type_cols, 
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−          "columns_length" => length_cols, "columns_order" => columns_order}.freeze
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−      end
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−    end
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−  end
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−end