Class: Dexter::ColumnResolver

Inherits:
Object
  • Object
show all
Includes:
Logging
Defined in:
lib/dexter/column_resolver.rb

Constant Summary

Constants included from Logging

Logging::COLOR_CODES

Instance Method Summary collapse

Methods included from Logging

#colorize, #log, #output

Constructor Details

#initialize(connection, queries, log_level:) ⇒ ColumnResolver

Returns a new instance of ColumnResolver.



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# File 'lib/dexter/column_resolver.rb', line 5

def initialize(connection, queries, log_level:)
  @connection = connection
  @queries = queries
  @log_level = log_level
end

Instance Method Details

#perform ⇒ Object 



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# File 'lib/dexter/column_resolver.rb', line 11

def perform
  tables = Set.new(@queries.flat_map(&:candidate_tables))
  columns = tables.any? ? self.columns(tables) : []
  columns_by_table = columns.group_by { |c| c[:table] }.transform_values { |v| v.to_h { |c| [c[:column], c] } }
  columns_by_table.default = {}

  @queries.each do |query|
    log "Finding columns: #{query.statement}" if @log_level == "debug3"
    columns = Set.new
    begin
      find_columns(query.tree).each do |col|
        last_col = col["fields"].last
        if last_col["String"]
          columns << last_col["String"]["sval"]
        end
      end
    rescue JSON::NestingError
      if @log_level.start_with?("debug")
        log colorize("ERROR: Cannot get columns", :red)
      end
    end

    possible_columns = []
    columns.each do |column|
      query.candidate_tables.each do |table|
        resolved = columns_by_table.dig(table, column)
        possible_columns << resolved if resolved
      end
    end
    # use all columns in tables from views (not ideal)
    (query.tables_from_views & query.candidate_tables).each do |table|
      possible_columns.concat(columns_by_table[table].values)
    end
    query.columns = possible_columns.uniq
  end
end