Class: SqlWrangler::Query

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(conn, sql_string, params = {}) ⇒ Query

Returns a new instance of Query.



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

def initialize(conn, sql_string, params={})
  @conn = conn
  @sql_string = sql_string
  @groupings = []
  @params = params
end

Instance Attribute Details

#conn ⇒ Object (readonly)

Returns the value of attribute conn.



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# File 'lib/sql_wrangler.rb', line 37

def conn
  @conn
end

#groupings ⇒ Object (readonly)

Returns the value of attribute groupings.



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# File 'lib/sql_wrangler.rb', line 36

def groupings
  @groupings
end

#params ⇒ Object

Returns the value of attribute params.



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# File 'lib/sql_wrangler.rb', line 38

def params
  @params
end

#sql_string ⇒ Object (readonly)

Returns the value of attribute sql_string.



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# File 'lib/sql_wrangler.rb', line 35

def sql_string
  @sql_string
end

Instance Method Details

#execute ⇒ Object 



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# File 'lib/sql_wrangler.rb', line 47

def execute
  raw_result = @conn.execute_sql(@sql_string, @params)
  init_groups_for_execution raw_result[0]
  return format_query_result(raw_result)
end

#format_query_result(raw_result) ⇒ Object 



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

def format_query_result(raw_result)
  formatted_result = []
  columns_by_index = get_columns_by_index raw_result[0]

  raw_result[1,raw_result.length-1].each do |raw_row|
    merge_row raw_row, @groupings, formatted_result, columns_by_index
  end

  return formatted_result
end

#get_columns_by_index(columns) ⇒ Object 



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# File 'lib/sql_wrangler.rb', line 64

def get_columns_by_index columns
  columns_by_index = {}
  (0..columns.length-1).each { |i| columns_by_index[i] = columns[i] }
  return columns_by_index
end

#get_existing_grouped_row(grouped_vals, grouped_data) ⇒ Object 



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# File 'lib/sql_wrangler.rb', line 118

def get_existing_grouped_row grouped_vals, grouped_data
  grouped_data.each do |grouped_row|
    if not grouped_vals.keys.any? { |key| grouped_vals[key] != grouped_row[key] }
      return grouped_row
    end
  end
  return nil
end

#group_by(columns, options = {}) ⇒ Object 



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# File 'lib/sql_wrangler.rb', line 127

def group_by columns, options = {}
  new_grouping = QueryGrouping.new(options[:into], columns)
  new_grouping.level = @groupings.length
  @groupings << new_grouping
  return self
end

#init_groups_for_execution(columns) ⇒ Object 



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# File 'lib/sql_wrangler.rb', line 70

def init_groups_for_execution columns
  used_indexes = []
  @groupings.each do |group|
    group.group_indexes = []
    group.content_indexes = []
    (0..(columns.length-1)).each do |i|
      if group.columns.any? { |c| c == columns[i] }
        used_indexes << i
        group.group_indexes << i
      elsif not used_indexes.any? { |used_index| used_index == i }
        group.content_indexes << i
      end
    end
  end
end

#merge_row(row, groups, grouped_data, columns_by_index) ⇒ Object 



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# File 'lib/sql_wrangler.rb', line 86

def merge_row(row, groups, grouped_data, columns_by_index)

  if not @groupings.any?
    flat_row = {}
    columns_by_index.each { |index, column| flat_row[column] = row[index] }
    grouped_data << flat_row
  elsif groups.any?
    this_group = groups[0]
    remaining_groups = groups[1, groups.length-1]
    grouped_vals = {}
    this_group.group_indexes.each { |index| grouped_vals[columns_by_index[index]] = row[index] }

    if grouped_vals.values.any? { |value| value != nil }
      grouped_row = get_existing_grouped_row grouped_vals, grouped_data

      if grouped_row == nil
        grouped_row = grouped_vals
        grouped_row[this_group.name] = [] if this_group != nil
        grouped_data << grouped_row
      end

      merge_row(row, remaining_groups, grouped_row[this_group.name], columns_by_index)
    end

  else
    leaf_data = {}
    @groupings.last.content_indexes.each { |i| leaf_data[columns_by_index[i]] = row[i] }
    grouped_data << leaf_data if leaf_data.values.any? { |value| value != nil }
  end

end