class PactBroker::DB::TableDependencyCalculator

Returns a list of the tables in the database in the order in which they can be truncated or dropped

Public Class Methods

call(connection) click to toggle source
# File lib/pact_broker/db/table_dependency_calculator.rb, line 8
def self.call connection
  new(connection).call
end
new(connection) click to toggle source
# File lib/pact_broker/db/table_dependency_calculator.rb, line 12
def initialize connection
  @connection = connection
end

Public Instance Methods

call() click to toggle source
# File lib/pact_broker/db/table_dependency_calculator.rb, line 16
def call
  ordered_table_names = []
  dependencies = @connection
    .tables
    .collect{|it| @connection.foreign_key_list(it)
    .collect{|fk| {from: it, to: fk[:table]} } }
    .flatten
    .uniq
  table_names = @connection.tables - [:schema_migrations, :schema_info]
  check(table_names, dependencies, ordered_table_names)
  ordered_table_names
end
check(table_names, deps, ordered_table_names) click to toggle source
# File lib/pact_broker/db/table_dependency_calculator.rb, line 33
def check table_names, deps, ordered_table_names
  return if table_names.size == 0
  remaining_dependencies = deps_on(table_names.first, deps) - ordered_table_names
  if remaining_dependencies.size == 0
    ordered_table_names << table_names.first
    check(table_names[1..-1], deps, ordered_table_names)
  else
    check((remaining_dependencies + table_names).uniq, deps, ordered_table_names)
  end
end
deps_on(table_name, deps) click to toggle source
# File lib/pact_broker/db/table_dependency_calculator.rb, line 29
def deps_on table_name, deps
  deps.select{ | d| d[:to] == table_name }.collect{ |d| d[:from] }
end