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Versions: 69
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Contents
module PactBroker
module DB
# Returns a list of the tables in the database in the order in which
# they can be truncated or dropped
class TableDependencyCalculator
def self.call connection
new(connection).call
end
def initialize connection
@connection = connection
end
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
def deps_on table_name, deps
deps.select{ | d| d[:to] == table_name }.collect{ |d| d[:from] }
end
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
end
end
end
Version data entries
69 entries across 69 versions & 1 rubygems