neurolang.datalog.chase.relational_algebra module¶

class neurolang.datalog.chase.relational_algebra.ChaseNamedRelationalAlgebraMixin¶

Bases: object

Conjunctive query solving using the algorithm 5.4.8 from Abiteboul et al [1]_ algorithm for named relational algebra.

..[1] S. Abiteboul, R. Hull, V. Vianu, Foundations of databases: (Addison Wesley, 1995), Addison-Wesley.

Methods

chase_step
compute_result_set
eliminate_already_computed
obtain_substitutions
rewrite_antecedent_equalities
rewrite_constants_in_consequent
rewrite_rule_consequent_constants_to_equalities
translate_conjunction_to_named_ra

chase_step(instance, rule, restriction_instance=None)¶

compute_result_set(rule, substitutions, instance, restriction_instance=None)¶

eliminate_already_computed(consequent, instance, substitutions)¶

obtain_substitutions(rule_predicates_iterator, instance, restriction_instance)¶

rewrite_antecedent_equalities(rule)¶

rewrite_constants_in_consequent(rule)¶

static rewrite_rule_consequent_constants_to_equalities(rule, new_args, new_equalities)¶

translate_conjunction_to_named_ra(conjunction)¶

class neurolang.datalog.chase.relational_algebra.ChaseRelationalAlgebraPlusCeriMixin¶

Bases: object

Conjunctive query solving using Ceri et al [1] algorithm for unnamed positive relational algebra.

[1]

S. Ceri, G. Gottlob, L. Lavazza, in Proceedings of the 12th International Conference on Very Large Data Bases (Morgan Kaufmann Publishers Inc., San Francisco, CA, USA, 1986; http://dl.acm.org/citation.cfm?id=645913.671468), VLDB ’86, pp. 395–402.

Methods

compute_substitutions
obtain_substitutions
translate_predicate
translate_predicate_process_argument
translate_predicate_process_argument_symbol
translate_to_ra_plus

compute_substitutions(result, projected_var_names)¶

obtain_substitutions(args_to_project, rule_predicates_iterator)¶

translate_predicate(pred_ra, column, args_to_project)¶

translate_predicate_process_argument(arg, local_selections, local_column, global_column, args_to_project)¶

translate_predicate_process_argument_symbol(arg, global_column, args_to_project)¶

translate_to_ra_plus(args_to_project, rule_predicates_iterator)¶

class neurolang.datalog.chase.relational_algebra.NamedRelationalAlgebraOptimiser(*args, **kwargs)¶

Bases: PushInSelections, ExpressionWalker

Attributes:

patterns: Property holding an iterator of triplets (pattern, guard, action).

Methods

`match`(expression)	Find the action for a given expression by going through the `patterns`.
`pattern_match`(pattern, expression)	Return `True` if `pattern` matches `expression`.
`type`

pattern_match_expression
pattern_match_expression_parameters
pattern_match_expression_tuple
pattern_match_tuple
process_expression
process_iterable_argument
push_and_rename_in_naturaljoin
push_selection_in_extended_projection
push_selection_in_groupby
push_selection_in_left
push_selection_in_leftnaturaljoin_left
push_selection_in_leftnaturaljoin_right
push_selection_in_outernaturaljoin_left
push_selection_in_outernaturaljoin_right
push_selection_in_projection
push_selection_in_replace_null
push_selection_in_right
walk

type = typing.Any¶