35d73d5541
This adds an `:order` keyword to `:find`. If present, the results of the query will be an ordered set, rather than an unordered set; rows will appear in an ordered defined by each `:order` entry. Each can be one of three things: - A var, `?x`, meaning "order by ?x ascending". - A pair, `(asc ?x)`, meaning "order by ?x ascending". - A pair, `(desc ?x)`, meaning "order by ?x descending". Values will be ordered in this sequence for asc, and in reverse for desc: 1. Entity IDs, in ascending numerical order. 2. Booleans, false then true. 3. Timestamps, in ascending numerical order. 4. Longs and doubles, intermixed, in ascending numerical order. 5. Strings, in ascending lexicographic order. 6. Keywords, in ascending lexicographic order, considering the entire ns/name pair as a single string separated by '/'. Subcommits: Pre: make bound_value public. Pre: generalize ErrorKind::UnboundVariable for use in order. Part 1: parse (direction, var) pairs. Part 2: parse :order clause into FindQuery. Part 3: include order variables in algebrized query. We add order variables to :with, so we can reuse its type tag projection logic, and so that we can phrase ordering in terms of variables rather than datoms columns. Part 4: produce SQL for order clauses.
237 lines
11 KiB
Rust
237 lines
11 KiB
Rust
// Copyright 2016 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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extern crate mentat_query_parser;
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extern crate mentat_query;
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extern crate edn;
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use edn::{
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NamespacedKeyword,
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PlainSymbol,
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};
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use mentat_query::{
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Direction,
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Element,
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FindSpec,
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FnArg,
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Order,
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OrJoin,
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OrWhereClause,
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Pattern,
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PatternNonValuePlace,
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PatternValuePlace,
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Predicate,
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UnifyVars,
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Variable,
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WhereClause,
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};
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use mentat_query_parser::parse_find_string;
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///! N.B., parsing a query can be done without reference to a DB.
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///! Processing the parsed query into something we can work with
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///! for planning involves interrogating the schema and idents in
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///! the store.
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///! See <https://github.com/mozilla/mentat/wiki/Querying> for more.
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#[test]
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fn can_parse_predicates() {
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let s = "[:find [?x ...] :where [?x _ ?y] [(< ?y 10)]]";
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let p = parse_find_string(s).unwrap();
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assert_eq!(p.find_spec,
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FindSpec::FindColl(Element::Variable(Variable::from_valid_name("?x"))));
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assert_eq!(p.where_clauses,
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vec![
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WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: PatternNonValuePlace::Placeholder,
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value: PatternValuePlace::Variable(Variable::from_valid_name("?y")),
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tx: PatternNonValuePlace::Placeholder,
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}),
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WhereClause::Pred(Predicate { operator: PlainSymbol::new("<"), args: vec![
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FnArg::Variable(Variable::from_valid_name("?y")), FnArg::EntidOrInteger(10),
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]}),
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]);
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}
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#[test]
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fn can_parse_simple_or() {
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let s = "[:find ?x . :where (or [?x _ 10] [?x _ 15])]";
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let p = parse_find_string(s).unwrap();
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assert_eq!(p.find_spec,
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FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x"))));
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assert_eq!(p.where_clauses,
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vec![
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WhereClause::OrJoin(OrJoin::new(
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UnifyVars::Implicit,
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vec![
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OrWhereClause::Clause(
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WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: PatternNonValuePlace::Placeholder,
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value: PatternValuePlace::EntidOrInteger(10),
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tx: PatternNonValuePlace::Placeholder,
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})),
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OrWhereClause::Clause(
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WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: PatternNonValuePlace::Placeholder,
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value: PatternValuePlace::EntidOrInteger(15),
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tx: PatternNonValuePlace::Placeholder,
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})),
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],
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)),
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]);
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}
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#[test]
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fn can_parse_unit_or_join() {
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let s = "[:find ?x . :where (or-join [?x] [?x _ 15])]";
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let p = parse_find_string(s).expect("to be able to parse find");
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assert_eq!(p.find_spec,
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FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x"))));
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assert_eq!(p.where_clauses,
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vec![
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WhereClause::OrJoin(OrJoin::new(
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UnifyVars::Explicit(vec![Variable::from_valid_name("?x")]),
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vec![
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OrWhereClause::Clause(
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WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: PatternNonValuePlace::Placeholder,
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value: PatternValuePlace::EntidOrInteger(15),
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tx: PatternNonValuePlace::Placeholder,
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})),
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],
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)),
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]);
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}
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#[test]
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fn can_parse_simple_or_join() {
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let s = "[:find ?x . :where (or-join [?x] [?x _ 10] [?x _ 15])]";
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let p = parse_find_string(s).unwrap();
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assert_eq!(p.find_spec,
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FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x"))));
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assert_eq!(p.where_clauses,
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vec![
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WhereClause::OrJoin(OrJoin::new(
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UnifyVars::Explicit(vec![Variable::from_valid_name("?x")]),
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vec![
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OrWhereClause::Clause(
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WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: PatternNonValuePlace::Placeholder,
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value: PatternValuePlace::EntidOrInteger(10),
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tx: PatternNonValuePlace::Placeholder,
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})),
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OrWhereClause::Clause(
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WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: PatternNonValuePlace::Placeholder,
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value: PatternValuePlace::EntidOrInteger(15),
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tx: PatternNonValuePlace::Placeholder,
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})),
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],
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)),
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]);
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}
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#[cfg(test)]
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fn ident(ns: &str, name: &str) -> PatternNonValuePlace {
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PatternNonValuePlace::Ident(::std::rc::Rc::new(NamespacedKeyword::new(ns, name)))
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}
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#[test]
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fn can_parse_simple_or_and_join() {
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let s = "[:find ?x . :where (or [?x _ 10] (and (or [?x :foo/bar ?y] [?x :foo/baz ?y]) [(< ?y 1)]))]";
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let p = parse_find_string(s).unwrap();
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assert_eq!(p.find_spec,
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FindSpec::FindScalar(Element::Variable(Variable::from_valid_name("?x"))));
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assert_eq!(p.where_clauses,
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vec![
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WhereClause::OrJoin(OrJoin::new(
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UnifyVars::Implicit,
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vec![
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OrWhereClause::Clause(
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WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: PatternNonValuePlace::Placeholder,
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value: PatternValuePlace::EntidOrInteger(10),
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tx: PatternNonValuePlace::Placeholder,
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})),
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OrWhereClause::And(
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vec![
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WhereClause::OrJoin(OrJoin::new(
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UnifyVars::Implicit,
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vec![
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OrWhereClause::Clause(WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: ident("foo", "bar"),
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value: PatternValuePlace::Variable(Variable::from_valid_name("?y")),
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tx: PatternNonValuePlace::Placeholder,
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})),
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OrWhereClause::Clause(WhereClause::Pattern(Pattern {
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source: None,
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entity: PatternNonValuePlace::Variable(Variable::from_valid_name("?x")),
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attribute: ident("foo", "baz"),
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value: PatternValuePlace::Variable(Variable::from_valid_name("?y")),
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tx: PatternNonValuePlace::Placeholder,
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})),
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],
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)),
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WhereClause::Pred(Predicate { operator: PlainSymbol::new("<"), args: vec![
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FnArg::Variable(Variable::from_valid_name("?y")), FnArg::EntidOrInteger(1),
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]}),
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],
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)
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],
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)),
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]);
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}
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#[test]
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fn can_parse_order_by() {
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let invalid = "[:find ?x :where [?x :foo/baz ?y] :order]";
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assert!(parse_find_string(invalid).is_err());
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// Defaults to ascending.
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let default = "[:find ?x :where [?x :foo/baz ?y] :order ?y]";
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assert_eq!(parse_find_string(default).unwrap().order,
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Some(vec![Order(Direction::Ascending, Variable::from_valid_name("?y"))]));
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let ascending = "[:find ?x :where [?x :foo/baz ?y] :order (asc ?y)]";
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assert_eq!(parse_find_string(ascending).unwrap().order,
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Some(vec![Order(Direction::Ascending, Variable::from_valid_name("?y"))]));
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let descending = "[:find ?x :where [?x :foo/baz ?y] :order (desc ?y)]";
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assert_eq!(parse_find_string(descending).unwrap().order,
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Some(vec![Order(Direction::Descending, Variable::from_valid_name("?y"))]));
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let mixed = "[:find ?x :where [?x :foo/baz ?y] :order (desc ?y) (asc ?x)]";
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assert_eq!(parse_find_string(mixed).unwrap().order,
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Some(vec![Order(Direction::Descending, Variable::from_valid_name("?y")),
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Order(Direction::Ascending, Variable::from_valid_name("?x"))]));
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}
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