Part 3: Handle ground. (#469) r=nalexander,rnewman

This version removes nalexander's lovely matrix code. It turned out
that scalar and tuple bindings are sufficiently different from coll
and rel -- they can directly apply as values in the query -- that
there was no point in jumping through hoops to turn those single
values into a matrix.

Furthermore, I've standardized us on a Vec<TypedValue>
representation for rectangular matrices, which should be much
more efficient, but would have required rewriting that code.

Finally, coll and rel are sufficiently different from each other
-- coll doesn't require processing nested collections -- that
my attempts to share code between them fell somewhat flat. I had
lots of nice ideas about zipping together cycles and such, but
ultimately I ended up with relatively straightforward, if a bit
repetitive, code.

The next commit will demonstrate the value of this work -- tests
that exercised scalar and tuple grounding now collapse down to
the simplest possible SQL.
This commit is contained in:
Nick Alexander 2017-04-26 15:50:17 -07:00 committed by Richard Newman
parent d04d22a6a6
commit 79fa0994b3
13 changed files with 1205 additions and 29 deletions

View file

@ -18,4 +18,5 @@ path = "../query"
path = "../query-parser" path = "../query-parser"
[dev-dependencies] [dev-dependencies]
itertools = "0.5"
maplit = "0.1" maplit = "0.1"

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@ -67,6 +67,7 @@ mod not;
mod pattern; mod pattern;
mod predicate; mod predicate;
mod resolve; mod resolve;
mod where_fn;
use validate::{ use validate::{
validate_not_join, validate_not_join,
@ -141,6 +142,7 @@ impl<K: Clone + Ord, V: Clone> Intersection<K> for BTreeMap<K, V> {
/// ///
/// - Ordinary pattern clauses turn into `FROM` parts and `WHERE` parts using `=`. /// - Ordinary pattern clauses turn into `FROM` parts and `WHERE` parts using `=`.
/// - Predicate clauses turn into the same, but with other functions. /// - Predicate clauses turn into the same, but with other functions.
/// - Function clauses turn into `WHERE` parts using function-specific comparisons.
/// - `not` turns into `NOT EXISTS` with `WHERE` clauses inside the subquery to /// - `not` turns into `NOT EXISTS` with `WHERE` clauses inside the subquery to
/// bind it to the outer variables, or adds simple `WHERE` clauses to the outer /// bind it to the outer variables, or adds simple `WHERE` clauses to the outer
/// clause. /// clause.
@ -228,6 +230,7 @@ impl Debug for ConjoiningClauses {
fmt.debug_struct("ConjoiningClauses") fmt.debug_struct("ConjoiningClauses")
.field("empty_because", &self.empty_because) .field("empty_because", &self.empty_because)
.field("from", &self.from) .field("from", &self.from)
.field("computed_tables", &self.computed_tables)
.field("wheres", &self.wheres) .field("wheres", &self.wheres)
.field("column_bindings", &self.column_bindings) .field("column_bindings", &self.column_bindings)
.field("input_variables", &self.input_variables) .field("input_variables", &self.input_variables)
@ -479,14 +482,15 @@ impl ConjoiningClauses {
/// Constrains the var if there's no existing type. /// Constrains the var if there's no existing type.
/// Marks as known-empty if it's impossible for this type to apply because there's a conflicting /// Marks as known-empty if it's impossible for this type to apply because there's a conflicting
/// type already known. /// type already known.
fn constrain_var_to_type(&mut self, variable: Variable, this_type: ValueType) { fn constrain_var_to_type(&mut self, var: Variable, this_type: ValueType) {
// Is there an existing mapping for this variable? // Is there an existing mapping for this variable?
// Any known inputs have already been added to known_types, and so if they conflict we'll // Any known inputs have already been added to known_types, and so if they conflict we'll
// spot it here. // spot it here.
if let Some(existing) = self.known_types.insert(variable.clone(), ValueTypeSet::of_one(this_type)) { let this_type_set = ValueTypeSet::of_one(this_type);
if let Some(existing) = self.known_types.insert(var.clone(), this_type_set) {
// There was an existing mapping. Does this type match? // There was an existing mapping. Does this type match?
if !existing.contains(this_type) { if !existing.contains(this_type) {
self.mark_known_empty(EmptyBecause::TypeMismatch(variable, existing, this_type)); self.mark_known_empty(EmptyBecause::TypeMismatch { var, existing, desired: this_type_set });
} }
} }
} }
@ -545,10 +549,9 @@ impl ConjoiningClauses {
Entry::Occupied(mut e) => { Entry::Occupied(mut e) => {
let intersected: ValueTypeSet = types.intersection(e.get()); let intersected: ValueTypeSet = types.intersection(e.get());
if intersected.is_empty() { if intersected.is_empty() {
let mismatching_type = types.exemplar().expect("types isn't none"); let reason = EmptyBecause::TypeMismatch { var: e.key().clone(),
let reason = EmptyBecause::TypeMismatch(e.key().clone(), existing: e.get().clone(),
e.get().clone(), desired: types };
mismatching_type);
empty_because = Some(reason); empty_because = Some(reason);
} }
// Always insert, even if it's empty! // Always insert, even if it's empty!
@ -838,6 +841,9 @@ impl ConjoiningClauses {
WhereClause::Pred(p) => { WhereClause::Pred(p) => {
self.apply_predicate(schema, p) self.apply_predicate(schema, p)
}, },
WhereClause::WhereFn(f) => {
self.apply_where_fn(schema, f)
},
WhereClause::OrJoin(o) => { WhereClause::OrJoin(o) => {
validate_or_join(&o)?; validate_or_join(&o)?;
self.apply_or_join(schema, o) self.apply_or_join(schema, o)

View file

@ -813,6 +813,7 @@ mod testing {
}); });
schema schema
} }
/// Test that if all the attributes in an `or` fail to resolve, the entire thing fails. /// Test that if all the attributes in an `or` fail to resolve, the entire thing fails.
#[test] #[test]
fn test_schema_based_failure() { fn test_schema_based_failure() {

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@ -801,7 +801,11 @@ mod testing {
assert!(cc.is_known_empty()); assert!(cc.is_known_empty());
assert_eq!(cc.empty_because.unwrap(), assert_eq!(cc.empty_because.unwrap(),
EmptyBecause::TypeMismatch(y.clone(), ValueTypeSet::of_one(ValueType::String), ValueType::Boolean)); EmptyBecause::TypeMismatch {
var: y.clone(),
existing: ValueTypeSet::of_one(ValueType::String),
desired: ValueTypeSet::of_one(ValueType::Boolean),
});
} }
#[test] #[test]
@ -839,7 +843,11 @@ mod testing {
assert!(cc.is_known_empty()); assert!(cc.is_known_empty());
assert_eq!(cc.empty_because.unwrap(), assert_eq!(cc.empty_because.unwrap(),
EmptyBecause::TypeMismatch(x.clone(), ValueTypeSet::of_one(ValueType::Ref), ValueType::Boolean)); EmptyBecause::TypeMismatch {
var: x.clone(),
existing: ValueTypeSet::of_one(ValueType::Ref),
desired: ValueTypeSet::of_one(ValueType::Boolean),
});
} }
#[test] #[test]

View file

@ -222,8 +222,10 @@ mod testing {
assert!(cc.is_known_empty()); assert!(cc.is_known_empty());
assert_eq!(cc.empty_because.unwrap(), assert_eq!(cc.empty_because.unwrap(),
EmptyBecause::TypeMismatch(y.clone(), EmptyBecause::TypeMismatch {
ValueTypeSet::of_numeric_types(), var: y.clone(),
ValueType::String)); existing: ValueTypeSet::of_numeric_types(),
desired: ValueTypeSet::of_one(ValueType::String),
});
} }
} }

View file

@ -0,0 +1,560 @@
// Copyright 2016 Mozilla
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
use std::rc::Rc;
use mentat_core::{
Schema,
SQLValueType,
TypedValue,
ValueType,
};
use mentat_query::{
Binding,
FnArg,
NonIntegerConstant,
Variable,
VariableOrPlaceholder,
WhereFn,
};
use clauses::{
ConjoiningClauses,
PushComputed,
};
use errors::{
BindingError,
ErrorKind,
Result,
};
use super::QualifiedAlias;
use types::{
ComputedTable,
EmptyBecause,
SourceAlias,
ValueTypeSet,
VariableColumn,
};
macro_rules! coerce_to_typed_value {
($var: ident, $val: ident, $types: expr, $type: path, $constructor: path) => { {
Ok(if !$types.contains($type) {
Impossible(EmptyBecause::TypeMismatch {
var: $var.clone(),
existing: $types,
desired: ValueTypeSet::of_one($type),
})
} else {
Val($constructor($val).into())
})
} }
}
enum ValueConversion {
Val(TypedValue),
Impossible(EmptyBecause),
}
/// Conversion of FnArgs to TypedValues.
impl ConjoiningClauses {
/// Convert the provided `FnArg` to a `TypedValue`.
/// The conversion depends on, and can fail because of:
/// - Existing known types of a variable to which this arg will be bound.
/// - Existing bindings of a variable `FnArg`.
fn typed_value_from_arg<'s>(&self, schema: &'s Schema, var: &Variable, arg: FnArg, known_types: ValueTypeSet) -> Result<ValueConversion> {
use self::ValueConversion::*;
if known_types.is_empty() {
// If this happens, it likely means the pattern has already failed!
return Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::any(),
}));
}
match arg {
// Longs are potentially ambiguous: they might be longs or entids.
FnArg::EntidOrInteger(x) => {
match (ValueType::Ref.accommodates_integer(x),
known_types.contains(ValueType::Ref),
known_types.contains(ValueType::Long)) {
(true, true, true) => {
// Ambiguous: this arg could be an entid or a long.
// We default to long.
Ok(Val(TypedValue::Long(x)))
},
(true, true, false) => {
// This can only be a ref.
Ok(Val(TypedValue::Ref(x)))
},
(_, false, true) => {
// This can only be a long.
Ok(Val(TypedValue::Long(x)))
},
(false, true, _) => {
// This isn't a valid ref, but that's the type to which this must conform!
Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::of_longs(),
}))
},
(_, false, false) => {
// Non-overlapping type sets.
Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::of_longs(),
}))
},
}
},
// If you definitely want to look up an ident, do it before running the query.
FnArg::IdentOrKeyword(x) => {
match (known_types.contains(ValueType::Ref),
known_types.contains(ValueType::Keyword)) {
(true, true) => {
// Ambiguous: this could be a keyword or an ident.
// Default to keyword.
Ok(Val(TypedValue::Keyword(Rc::new(x))))
},
(true, false) => {
// This can only be an ident. Look it up!
match schema.get_entid(&x).map(TypedValue::Ref) {
Some(e) => Ok(Val(e)),
None => Ok(Impossible(EmptyBecause::UnresolvedIdent(x.clone()))),
}
},
(false, true) => {
Ok(Val(TypedValue::Keyword(Rc::new(x))))
},
(false, false) => {
Ok(Impossible(EmptyBecause::TypeMismatch {
var: var.clone(),
existing: known_types,
desired: ValueTypeSet::of_keywords(),
}))
},
}
},
FnArg::Variable(in_var) => {
// TODO: technically you could ground an existing variable inside the query….
if !self.input_variables.contains(&in_var) {
bail!(ErrorKind::UnboundVariable((*in_var.0).clone()));
}
match self.bound_value(&in_var) {
// The type is already known if it's a bound variable….
Some(ref in_value) => Ok(Val(in_value.clone())),
None => bail!(ErrorKind::UnboundVariable((*in_var.0).clone())),
}
},
// This isn't implemented yet.
FnArg::Constant(NonIntegerConstant::BigInteger(_)) => unimplemented!(),
// These don't make sense here.
FnArg::Vector(_) |
FnArg::SrcVar(_) => bail!(ErrorKind::InvalidGroundConstant),
// These are all straightforward.
FnArg::Constant(NonIntegerConstant::Boolean(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Boolean, TypedValue::Boolean)
},
FnArg::Constant(NonIntegerConstant::Instant(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Instant, TypedValue::Instant)
},
FnArg::Constant(NonIntegerConstant::Uuid(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Uuid, TypedValue::Uuid)
},
FnArg::Constant(NonIntegerConstant::Float(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::Double, TypedValue::Double)
},
FnArg::Constant(NonIntegerConstant::Text(x)) => {
coerce_to_typed_value!(var, x, known_types, ValueType::String, TypedValue::String)
},
}
}
}
/// Application of `where` functions.
impl ConjoiningClauses {
/// There are several kinds of functions binding variables in our Datalog:
/// - A set of functions like `ground`, fulltext` and `get-else` that are translated into SQL
/// `VALUES`, `MATCH`, or `JOIN`, yielding bindings.
/// - In the future, some functions that are implemented via function calls in SQLite.
///
/// At present we have implemented only a limited selection of functions.
pub fn apply_where_fn<'s>(&mut self, schema: &'s Schema, where_fn: WhereFn) -> Result<()> {
// Because we'll be growing the set of built-in functions, handling each differently, and
// ultimately allowing user-specified functions, we match on the function name first.
match where_fn.operator.0.as_str() {
"ground" => self.apply_ground(schema, where_fn),
_ => bail!(ErrorKind::UnknownFunction(where_fn.operator.clone())),
}
}
fn apply_ground_place<'s>(&mut self, schema: &'s Schema, var: VariableOrPlaceholder, arg: FnArg) -> Result<()> {
match var {
VariableOrPlaceholder::Placeholder => Ok(()),
VariableOrPlaceholder::Variable(var) => self.apply_ground_var(schema, var, arg),
}
}
/// Constrain the CC to associate the given var with the given ground argument.
/// Marks known-empty on failure.
fn apply_ground_var<'s>(&mut self, schema: &'s Schema, var: Variable, arg: FnArg) -> Result<()> {
let known_types = self.known_type_set(&var);
match self.typed_value_from_arg(schema, &var, arg, known_types)? {
ValueConversion::Val(value) => self.apply_ground_value(var, value),
ValueConversion::Impossible(because) => {
self.mark_known_empty(because);
Ok(())
},
}
}
/// Marks known-empty on failure.
fn apply_ground_value(&mut self, var: Variable, value: TypedValue) -> Result<()> {
if let Some(existing) = self.bound_value(&var) {
if existing != value {
self.mark_known_empty(EmptyBecause::ConflictingBindings {
var: var.clone(),
existing: existing.clone(),
desired: value,
});
return Ok(())
}
} else {
self.bind_value(&var, value.clone());
}
// Check to see whether this variable is already associated to a column.
// If so, we want to add an equality filter (or, in the future, redo the existing patterns).
if let Some(QualifiedAlias(table, column)) = self.column_bindings
.get(&var)
.and_then(|vec| vec.get(0).cloned()) {
self.constrain_column_to_constant(table, column, value);
}
Ok(())
}
/// Take a relation: a matrix of values which will successively bind to named variables of
/// the provided types.
/// Construct a computed table to yield this relation.
/// This function will panic if some invariants are not met.
fn collect_named_bindings<'s>(&mut self, schema: &'s Schema, names: Vec<Variable>, types: Vec<ValueType>, values: Vec<TypedValue>) {
if values.is_empty() {
return;
}
assert!(!names.is_empty());
assert_eq!(names.len(), types.len());
assert!(values.len() >= names.len());
assert_eq!(values.len() % names.len(), 0); // It's an exact multiple.
let named_values = ComputedTable::NamedValues {
names: names.clone(),
values: values,
};
let table = self.computed_tables.push_computed(named_values);
let alias = self.next_alias_for_table(table);
// Stitch the computed table into column_bindings, so we get cross-linking.
for (name, ty) in names.iter().zip(types.into_iter()) {
self.constrain_var_to_type(name.clone(), ty);
self.bind_column_to_var(schema, alias.clone(), VariableColumn::Variable(name.clone()), name.clone());
}
self.from.push(SourceAlias(table, alias));
}
pub fn apply_ground<'s>(&mut self, schema: &'s Schema, where_fn: WhereFn) -> Result<()> {
if where_fn.args.len() != 1 {
bail!(ErrorKind::InvalidNumberOfArguments(where_fn.operator.clone(), where_fn.args.len(), 1));
}
let mut args = where_fn.args.into_iter();
if where_fn.binding.is_empty() {
// The binding must introduce at least one bound variable.
bail!(ErrorKind::InvalidBinding(where_fn.operator.clone(), BindingError::NoBoundVariable));
}
if !where_fn.binding.is_valid() {
// The binding must not duplicate bound variables.
bail!(ErrorKind::InvalidBinding(where_fn.operator.clone(), BindingError::RepeatedBoundVariable));
}
// Scalar and tuple bindings are a little special: because there's only one value,
// we can immediately substitute the value as a known value in the CC, additionally
// generating a WHERE clause if columns have already been bound.
match (where_fn.binding, args.next().unwrap()) {
(Binding::BindScalar(var), constant) =>
self.apply_ground_var(schema, var, constant),
(Binding::BindTuple(places), FnArg::Vector(children)) => {
// Just the same, but we bind more than one column at a time.
if children.len() != places.len() {
// Number of arguments don't match the number of values. TODO: better error message.
bail!(ErrorKind::GroundBindingsMismatch);
}
for (place, arg) in places.into_iter().zip(children.into_iter()) {
self.apply_ground_place(schema, place, arg)? // TODO: short-circuit on impossible.
}
Ok(())
},
// Collection bindings and rel bindings are similar in that they are both
// implemented as a subquery with a projection list and a set of values.
// The difference is that BindColl has only a single variable, and its values
// are all in a single structure. That makes it substantially simpler!
(Binding::BindColl(var), FnArg::Vector(children)) => {
if children.is_empty() {
bail!(ErrorKind::InvalidGroundConstant);
}
// Turn a collection of arguments into a Vec of `TypedValue`s of the same type.
let known_types = self.known_type_set(&var);
// Check that every value has the same type.
let mut accumulated_types = ValueTypeSet::none();
let mut skip: Option<EmptyBecause> = None;
let values = children.into_iter()
.filter_map(|arg| -> Option<Result<TypedValue>> {
// We need to get conversion errors out.
// We also want to mark known-empty on impossibilty, but
// still detect serious errors.
match self.typed_value_from_arg(schema, &var, arg, known_types) {
Ok(ValueConversion::Val(tv)) => {
if accumulated_types.insert(tv.value_type()) &&
!accumulated_types.is_unit() {
// Values not all of the same type.
Some(Err(ErrorKind::InvalidGroundConstant.into()))
} else {
Some(Ok(tv))
}
},
Ok(ValueConversion::Impossible(because)) => {
// Skip this value.
skip = Some(because);
None
},
Err(e) => Some(Err(e.into())),
}
})
.collect::<Result<Vec<TypedValue>>>()?;
if values.is_empty() {
let because = skip.expect("we skipped all rows for a reason");
self.mark_known_empty(because);
return Ok(());
}
// Otherwise, we now have the values and the type.
let types = vec![accumulated_types.exemplar().unwrap()];
let names = vec![var.clone()];
self.collect_named_bindings(schema, names, types, values);
Ok(())
},
(Binding::BindRel(places), FnArg::Vector(rows)) => {
if rows.is_empty() {
bail!(ErrorKind::InvalidGroundConstant);
}
// Grab the known types to which these args must conform, and track
// the places that won't be bound in the output.
let template: Vec<Option<(Variable, ValueTypeSet)>> =
places.iter()
.map(|x| match x {
&VariableOrPlaceholder::Placeholder => None,
&VariableOrPlaceholder::Variable(ref v) => Some((v.clone(), self.known_type_set(v))),
})
.collect();
// The expected 'width' of the matrix is the number of named variables.
let full_width = places.len();
let names: Vec<Variable> = places.into_iter().filter_map(|x| x.into_var()).collect();
let expected_width = names.len();
let expected_rows = rows.len();
if expected_width == 0 {
// They can't all be placeholders.
bail!(ErrorKind::InvalidGroundConstant);
}
// Accumulate values into `matrix` and types into `a_t_f_c`.
// This representation of a rectangular matrix is more efficient than one composed
// of N separate vectors.
let mut matrix = Vec::with_capacity(expected_width * expected_rows);
let mut accumulated_types_for_columns = vec![ValueTypeSet::none(); expected_width];
// Loop so we can bail out.
let mut skipped_all: Option<EmptyBecause> = None;
for row in rows.into_iter() {
match row {
FnArg::Vector(cols) => {
// Make sure that every row is the same length.
if cols.len() != full_width {
bail!(ErrorKind::InvalidGroundConstant);
}
// TODO: don't accumulate twice.
let mut vals = Vec::with_capacity(expected_width);
let mut skip: Option<EmptyBecause> = None;
for (col, pair) in cols.into_iter().zip(template.iter()) {
// Now we have (val, Option<(name, known_types)>). Silly,
// but this is how we iter!
// Convert each item in the row.
// If any value in the row is impossible, then skip the row.
// If all rows are impossible, fail the entire CC.
if let &Some(ref pair) = pair {
match self.typed_value_from_arg(schema, &pair.0, col, pair.1)? {
ValueConversion::Val(tv) => vals.push(tv),
ValueConversion::Impossible(because) => {
// Skip this row. It cannot produce bindings.
skip = Some(because);
break;
},
}
}
}
if skip.is_some() {
// Skip this row and record why, in case we skip all.
skipped_all = skip;
continue;
}
// Accumulate the values into the matrix and the types into the type set.
for (val, acc) in vals.into_iter().zip(accumulated_types_for_columns.iter_mut()) {
let inserted = acc.insert(val.value_type());
if inserted && !acc.is_unit() {
// Heterogeneous types.
bail!(ErrorKind::InvalidGroundConstant);
}
matrix.push(val);
}
},
_ => bail!(ErrorKind::InvalidGroundConstant),
}
}
// Do we have rows? If not, the CC cannot succeed.
if matrix.is_empty() {
// We will either have bailed or will have accumulated *something* into the matrix,
// so we can safely unwrap here.
self.mark_known_empty(skipped_all.expect("we skipped for a reason"));
return Ok(());
}
// Take the single type from each set. We know there's only one: we got at least one
// type, 'cos we bailed out for zero rows, and we also bailed out each time we
// inserted a second type.
// By restricting to homogeneous columns, we greatly simplify projection. In the
// future, we could loosen this restriction, at the cost of projecting (some) value
// type tags. If and when we want to algebrize in two phases and allow for
// late-binding input variables, we'll probably be able to loosen this restriction
// with little penalty.
let types = accumulated_types_for_columns.into_iter()
.map(|x| x.exemplar().unwrap())
.collect();
self.collect_named_bindings(schema, names, types, matrix);
Ok(())
},
(_, _) => bail!(ErrorKind::InvalidGroundConstant),
}
}
}
#[cfg(test)]
mod testing {
use super::*;
use mentat_core::{
Attribute,
ValueType,
};
use mentat_query::{
Binding,
FnArg,
NamespacedKeyword,
PlainSymbol,
Variable,
};
use clauses::{
add_attribute,
associate_ident,
};
use types::{
ValueTypeSet,
};
#[test]
fn test_apply_ground() {
let vz = Variable::from_valid_name("?z");
let mut cc = ConjoiningClauses::default();
let mut schema = Schema::default();
associate_ident(&mut schema, NamespacedKeyword::new("foo", "fts"), 100);
add_attribute(&mut schema, 100, Attribute {
value_type: ValueType::String,
index: true,
fulltext: true,
..Default::default()
});
// It's awkward enough to write these expansions that we give the details for the simplest
// case only. See the tests of the translator for more extensive (albeit looser) coverage.
let op = PlainSymbol::new("ground");
cc.apply_ground(&schema, WhereFn {
operator: op,
args: vec![
FnArg::EntidOrInteger(10),
],
binding: Binding::BindScalar(vz.clone()),
}).expect("to be able to apply_ground");
assert!(!cc.is_known_empty());
// Finally, expand column bindings.
cc.expand_column_bindings();
assert!(!cc.is_known_empty());
let clauses = cc.wheres;
assert_eq!(clauses.len(), 0);
let column_bindings = cc.column_bindings;
assert_eq!(column_bindings.len(), 0); // Scalar doesn't need this.
let known_types = cc.known_types;
assert_eq!(known_types.len(), 1);
assert_eq!(known_types.get(&vz).expect("to know the type of ?z"),
&ValueTypeSet::of_one(ValueType::Long));
let value_bindings = cc.value_bindings;
assert_eq!(value_bindings.len(), 1);
assert_eq!(value_bindings.get(&vz).expect("to have a value for ?z"),
&TypedValue::Long(10)); // We default to Long instead of entid.
}
}

View file

@ -10,12 +10,20 @@
extern crate mentat_query; extern crate mentat_query;
use mentat_core::ValueType; use mentat_core::{
ValueType,
};
use self::mentat_query::{ use self::mentat_query::{
PlainSymbol, PlainSymbol,
}; };
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum BindingError {
NoBoundVariable,
RepeatedBoundVariable, // TODO: include repeated variable(s).
}
error_chain! { error_chain! {
types { types {
Error, ErrorKind, ResultExt, Result; Error, ErrorKind, ResultExt, Result;
@ -32,9 +40,9 @@ error_chain! {
display("no function named {}", name) display("no function named {}", name)
} }
InvalidNumberOfArguments(name: PlainSymbol, number: usize, expected: usize) { InvalidNumberOfArguments(function: PlainSymbol, number: usize, expected: usize) {
description("invalid number of arguments") description("invalid number of arguments")
display("invalid number of arguments to {}: expected {}, got {}.", name, expected, number) display("invalid number of arguments to {}: expected {}, got {}.", function, expected, number)
} }
UnboundVariable(name: PlainSymbol) { UnboundVariable(name: PlainSymbol) {
@ -42,6 +50,21 @@ error_chain! {
display("unbound variable: {}", name) display("unbound variable: {}", name)
} }
InvalidBinding(function: PlainSymbol, binding_error: BindingError) {
description("invalid binding")
display("invalid binding for {}: {:?}.", function, binding_error)
}
GroundBindingsMismatch {
description("mismatched bindings in ground")
display("mismatched bindings in ground")
}
InvalidGroundConstant {
// TODO: flesh this out.
description("invalid expression in ground constant")
display("invalid expression in ground constant")
}
InvalidArgument(function: PlainSymbol, expected_type: &'static str, position: usize) { InvalidArgument(function: PlainSymbol, expected_type: &'static str, position: usize) {
description("invalid argument") description("invalid argument")

View file

@ -46,6 +46,7 @@ use mentat_query::{
}; };
pub use errors::{ pub use errors::{
BindingError,
Error, Error,
ErrorKind, ErrorKind,
Result, Result,

View file

@ -53,6 +53,10 @@ pub enum ComputedTable {
type_extraction: BTreeSet<Variable>, type_extraction: BTreeSet<Variable>,
arms: Vec<::clauses::ConjoiningClauses>, arms: Vec<::clauses::ConjoiningClauses>,
}, },
NamedValues {
names: Vec<Variable>,
values: Vec<TypedValue>,
},
} }
impl DatomsTable { impl DatomsTable {
@ -419,8 +423,8 @@ impl Debug for ColumnConstraint {
#[derive(PartialEq, Clone)] #[derive(PartialEq, Clone)]
pub enum EmptyBecause { pub enum EmptyBecause {
// Var, existing, desired. ConflictingBindings { var: Variable, existing: TypedValue, desired: TypedValue },
TypeMismatch(Variable, ValueTypeSet, ValueType), TypeMismatch { var: Variable, existing: ValueTypeSet, desired: ValueTypeSet },
NoValidTypes(Variable), NoValidTypes(Variable),
NonNumericArgument, NonNumericArgument,
NonStringFulltextValue, NonStringFulltextValue,
@ -436,7 +440,11 @@ impl Debug for EmptyBecause {
fn fmt(&self, f: &mut Formatter) -> ::std::fmt::Result { fn fmt(&self, f: &mut Formatter) -> ::std::fmt::Result {
use self::EmptyBecause::*; use self::EmptyBecause::*;
match self { match self {
&TypeMismatch(ref var, ref existing, ref desired) => { &ConflictingBindings { ref var, ref existing, ref desired } => {
write!(f, "Var {:?} can't be {:?} because it's already bound to {:?}",
var, desired, existing)
},
&TypeMismatch { ref var, ref existing, ref desired } => {
write!(f, "Type mismatch: {:?} can't be {:?}, because it's already {:?}", write!(f, "Type mismatch: {:?} can't be {:?}, because it's already {:?}",
var, desired, existing) var, desired, existing)
}, },

View file

@ -0,0 +1,315 @@
// Copyright 2016 Mozilla
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
extern crate mentat_core;
extern crate mentat_query;
extern crate mentat_query_algebrizer;
extern crate mentat_query_parser;
use mentat_core::{
Attribute,
Entid,
Schema,
ValueType,
TypedValue,
};
use mentat_query_parser::{
parse_find_string,
};
use mentat_query::{
NamespacedKeyword,
PlainSymbol,
Variable,
};
use mentat_query_algebrizer::{
BindingError,
ConjoiningClauses,
ComputedTable,
Error,
ErrorKind,
algebrize,
};
// These are helpers that tests use to build Schema instances.
#[cfg(test)]
fn associate_ident(schema: &mut Schema, i: NamespacedKeyword, e: Entid) {
schema.entid_map.insert(e, i.clone());
schema.ident_map.insert(i.clone(), e);
}
#[cfg(test)]
fn add_attribute(schema: &mut Schema, e: Entid, a: Attribute) {
schema.schema_map.insert(e, a);
}
fn prepopulated_schema() -> Schema {
let mut schema = Schema::default();
associate_ident(&mut schema, NamespacedKeyword::new("foo", "name"), 65);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "knows"), 66);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "parent"), 67);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "age"), 68);
associate_ident(&mut schema, NamespacedKeyword::new("foo", "height"), 69);
add_attribute(&mut schema, 65, Attribute {
value_type: ValueType::String,
multival: false,
..Default::default()
});
add_attribute(&mut schema, 66, Attribute {
value_type: ValueType::Ref,
multival: true,
..Default::default()
});
add_attribute(&mut schema, 67, Attribute {
value_type: ValueType::String,
multival: true,
..Default::default()
});
add_attribute(&mut schema, 68, Attribute {
value_type: ValueType::Long,
multival: false,
..Default::default()
});
add_attribute(&mut schema, 69, Attribute {
value_type: ValueType::Long,
multival: false,
..Default::default()
});
schema
}
fn bails(schema: &Schema, input: &str) -> Error {
let parsed = parse_find_string(input).expect("query input to have parsed");
algebrize(schema.into(), parsed).expect_err("algebrize to have failed")
}
fn alg(schema: &Schema, input: &str) -> ConjoiningClauses {
let parsed = parse_find_string(input).expect("query input to have parsed");
algebrize(schema.into(), parsed).expect("algebrizing to have succeeded").cc
}
#[test]
fn test_ground_doesnt_bail_for_type_conflicts() {
// We know `?x` to be a ref, but we're attempting to ground it to a Double.
// The query can return no results.
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground 9.95) ?x]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_tuple_fails_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [5 9.95]) [?x ?p]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_scalar_fails_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground true) ?p]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_coll_skips_impossible() {
// We know `?x` to be a ref, but we're attempting to ground it to a Double.
// The query can return no results.
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [5 9.95 11]) [?x ...]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x")],
values: vec![TypedValue::Ref(5), TypedValue::Ref(11)],
});
}
#[test]
fn test_ground_coll_fails_if_all_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [5.1 5.2]) [?p ...]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_rel_skips_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[8 "foo"] [5 7] [9.95 9] [11 12]]) [[?x ?p]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x"), Variable::from_valid_name("?p")],
values: vec![TypedValue::Ref(5), TypedValue::Ref(7), TypedValue::Ref(11), TypedValue::Ref(12)],
});
}
#[test]
fn test_ground_rel_fails_if_all_impossible() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[11 5.1] [12 5.2]]) [[?x ?p]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_tuple_rejects_all_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [8 "foo" 3]) [_ _ _]]]"#;
let schema = prepopulated_schema();
bails(&schema, &q);
}
#[test]
fn test_ground_rel_rejects_all_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[8 "foo"]]) [[_ _]]]]"#;
let schema = prepopulated_schema();
bails(&schema, &q);
}
#[test]
fn test_ground_tuple_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [8 "foo" 3]) [?x _ ?p]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.bound_value(&Variable::from_valid_name("?x")), Some(TypedValue::Ref(8)));
assert_eq!(cc.bound_value(&Variable::from_valid_name("?p")), Some(TypedValue::Ref(3)));
}
#[test]
fn test_ground_rel_placeholders() {
let q = r#"[:find ?x :where [?x :foo/knows ?p] [(ground [[8 "foo" 3] [5 false 7] [5 9.95 9]]) [[?x _ ?p]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x"), Variable::from_valid_name("?p")],
values: vec![
TypedValue::Ref(8),
TypedValue::Ref(3),
TypedValue::Ref(5),
TypedValue::Ref(7),
TypedValue::Ref(5),
TypedValue::Ref(9),
],
});
}
// Nothing to do with ground, but while we're here…
#[test]
fn test_multiple_reference_type_failure() {
let q = r#"[:find ?x :where [?x :foo/age ?y] [?x :foo/knows ?y]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_some());
}
#[test]
fn test_ground_tuple_infers_types() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [8 10]) [?x ?v]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.bound_value(&Variable::from_valid_name("?x")), Some(TypedValue::Ref(8)));
assert_eq!(cc.bound_value(&Variable::from_valid_name("?v")), Some(TypedValue::Long(10)));
}
#[test]
fn test_ground_rel_infers_types() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [[8 10]]) [[?x ?v]]]]"#;
let schema = prepopulated_schema();
let cc = alg(&schema, &q);
assert!(cc.empty_because.is_none());
assert_eq!(cc.computed_tables[0], ComputedTable::NamedValues {
names: vec![Variable::from_valid_name("?x"), Variable::from_valid_name("?v")],
values: vec![TypedValue::Ref(8), TypedValue::Long(10)],
});
}
#[test]
fn test_ground_coll_heterogeneous_types() {
let q = r#"[:find ?x :where [?x _ ?v] [(ground [false 8.5]) [?v ...]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidGroundConstant, _) => {
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_rel_heterogeneous_types() {
let q = r#"[:find ?x :where [?x _ ?v] [(ground [[false] [5]]) [[?v]]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidGroundConstant, _) => {
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_tuple_duplicate_vars() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [8 10]) [?x ?x]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidBinding(v, e), _) => {
assert_eq!(v, PlainSymbol::new("ground"));
assert_eq!(e, BindingError::RepeatedBoundVariable);
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_rel_duplicate_vars() {
let q = r#"[:find ?x :where [?x :foo/age ?v] [(ground [[8 10]]) [[?x ?x]]]]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::InvalidBinding(v, e), _) => {
assert_eq!(v, PlainSymbol::new("ground"));
assert_eq!(e, BindingError::RepeatedBoundVariable);
},
_ => {
panic!();
},
}
}
#[test]
fn test_ground_nonexistent_variable_invalid() {
let q = r#"[:find ?x ?e :where [?e _ ?x] (not [(ground 17) ?v])]"#;
let schema = prepopulated_schema();
let e = bails(&schema, &q);
match e {
Error(ErrorKind::UnboundVariable(PlainSymbol(v)), _) => {
assert_eq!(v, "?v".to_string());
},
_ => {
panic!();
},
}
}

View file

@ -52,6 +52,7 @@ use mentat_query_sql::{
SelectQuery, SelectQuery,
TableList, TableList,
TableOrSubquery, TableOrSubquery,
Values,
}; };
trait ToConstraint { trait ToConstraint {
@ -240,7 +241,13 @@ fn table_for_computed(computed: ComputedTable, alias: TableAlias) -> TableOrSubq
}, },
ComputedTable::Subquery(subquery) => { ComputedTable::Subquery(subquery) => {
TableOrSubquery::Subquery(Box::new(cc_to_exists(subquery))) TableOrSubquery::Subquery(Box::new(cc_to_exists(subquery)))
} },
ComputedTable::NamedValues {
names, values,
} => {
// We assume column homogeneity, so we won't have any type tag columns.
TableOrSubquery::Values(Values::Named(names, values), alias)
},
} }
} }

View file

@ -550,3 +550,177 @@ fn test_complex_nested_or_join_type_projection() {
LIMIT 1"); LIMIT 1");
assert_eq!(args, vec![]); assert_eq!(args, vec![]);
} }
#[test]
fn test_ground_scalar() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x . :where [(ground "yyy") ?x]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT $v0 AS `?x` LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find ?x . :in ?v :where [(ground ?v) ?x]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?v"), TypedValue::String(Rc::new("aaa".into())))]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
assert_eq!(sql, "SELECT $v0 AS `?x` LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "aaa"),]);
}
#[test]
fn test_ground_tuple() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x ?y :where [(ground [1 "yyy"]) [?x ?y]]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT 1 AS `?x`, $v0 AS `?y`");
assert_eq!(args, vec![make_arg("$v0", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find [?x ?y] :in ?u ?v :where [(ground [?u ?v]) [?x ?y]]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?u"), TypedValue::Long(2)),
(Variable::from_valid_name("?v"), TypedValue::String(Rc::new("aaa".into()))),]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
// TODO: treat 2 as an input variable that could be bound late, rather than eagerly binding it.
assert_eq!(sql, "SELECT 2 AS `?x`, $v0 AS `?y` LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "aaa"),]);
}
#[test]
fn test_ground_coll() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x :where [(ground ["xxx" "yyy"]) [?x ...]]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x` FROM \
(SELECT 0 AS `?x` WHERE 0 UNION ALL VALUES ($v0), ($v1)) AS `c00`");
assert_eq!(args, vec![make_arg("$v0", "xxx"),
make_arg("$v1", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find ?x :in ?u ?v :where [(ground [?u ?v]) [?x ...]]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?u"), TypedValue::Long(2)),
(Variable::from_valid_name("?v"), TypedValue::Long(3)),]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
// TODO: treat 2 and 3 as input variables that could be bound late, rather than eagerly binding.
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x` FROM \
(SELECT 0 AS `?x` WHERE 0 UNION ALL VALUES (2), (3)) AS `c00`");
assert_eq!(args, vec![]);
}
#[test]
fn test_ground_rel() {
let schema = prepopulated_schema();
// Verify that we accept inline constants.
let query = r#"[:find ?x ?y :where [(ground [[1 "xxx"] [2 "yyy"]]) [[?x ?y]]]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x`, `c00`.`?y` AS `?y` FROM \
(SELECT 0 AS `?x`, 0 AS `?y` WHERE 0 UNION ALL VALUES (1, $v0), (2, $v1)) AS `c00`");
assert_eq!(args, vec![make_arg("$v0", "xxx"),
make_arg("$v1", "yyy")]);
// Verify that we accept bound input constants.
let query = r#"[:find ?x ?y :in ?u ?v :where [(ground [[?u 1] [?v 2]]) [[?x ?y]]]]"#;
let inputs = QueryInputs::with_value_sequence(vec![(Variable::from_valid_name("?u"), TypedValue::Long(3)),
(Variable::from_valid_name("?v"), TypedValue::Long(4)),]);
let SQLQuery { sql, args } = translate_with_inputs(&schema, query, inputs);
// TODO: treat 3 and 4 as input variables that could be bound late, rather than eagerly binding.
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x`, `c00`.`?y` AS `?y` FROM \
(SELECT 0 AS `?x`, 0 AS `?y` WHERE 0 UNION ALL VALUES (3, 1), (4, 2)) AS `c00`");
assert_eq!(args, vec![]);
}
#[test]
fn test_compound_with_ground() {
let schema = prepopulated_schema();
// Verify that we can use the resulting CCs as children in compound CCs.
let query = r#"[:find ?x :where (or [(ground "yyy") ?x]
[(ground "zzz") ?x])]"#;
let SQLQuery { sql, args } = translate(&schema, query);
// This is confusing because the computed tables (like `c00`) are numbered sequentially in each
// arm of the `or` rather than numbered globally. But SQLite scopes the names correctly, so it
// works. In the future, we might number the computed tables globally to make this more clear.
assert_eq!(sql, "SELECT DISTINCT `c00`.`?x` AS `?x` FROM (\
SELECT $v0 AS `?x` UNION \
SELECT $v1 AS `?x`) AS `c00`");
assert_eq!(args, vec![make_arg("$v0", "yyy"),
make_arg("$v1", "zzz"),]);
// Verify that we can use ground to constrain the bindings produced by earlier clauses.
let query = r#"[:find ?x . :where [_ :foo/bar ?x] [(ground "yyy") ?x]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT $v0 AS `?x` FROM `datoms` AS `datoms00` \
WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "yyy")]);
// Verify that we can further constrain the bindings produced by our clause.
let query = r#"[:find ?x . :where [(ground "yyy") ?x] [_ :foo/bar ?x]]"#;
let SQLQuery { sql, args } = translate(&schema, query);
assert_eq!(sql, "SELECT $v0 AS `?x` FROM `datoms` AS `datoms00` \
WHERE `datoms00`.a = 99 AND `datoms00`.v = $v0 LIMIT 1");
assert_eq!(args, vec![make_arg("$v0", "yyy")]);
}
#[test]
fn test_unbound_attribute_with_ground_entity() {
let query = r#"[:find ?x ?v :where [?x _ ?v] (not [(ground 17) ?x])]"#;
let schema = prepopulated_schema();
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `all_datoms00`.e AS `?x`, \
`all_datoms00`.v AS `?v`, \
`all_datoms00`.value_type_tag AS `?v_value_type_tag` \
FROM `all_datoms` AS `all_datoms00` \
WHERE NOT EXISTS (SELECT 1 WHERE `all_datoms00`.e = 17)");
}
#[test]
fn test_unbound_attribute_with_ground() {
// TODO: this needs to expand the type code. #475.
let query = r#"[:find ?x :where [?x _ ?v] (not [(ground 5) ?v])]"#;
let schema = prepopulated_schema();
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql, "SELECT DISTINCT `all_datoms00`.e AS `?x` FROM `all_datoms` AS `all_datoms00` \
WHERE NOT EXISTS (SELECT 1 WHERE `all_datoms00`.v = 5)");
}
#[test]
fn test_not_with_ground() {
let mut schema = prepopulated_schema();
associate_ident(&mut schema, NamespacedKeyword::new("db", "valueType"), 7);
associate_ident(&mut schema, NamespacedKeyword::new("db.type", "ref"), 23);
associate_ident(&mut schema, NamespacedKeyword::new("db.type", "bool"), 28);
associate_ident(&mut schema, NamespacedKeyword::new("db.type", "instant"), 29);
add_attribute(&mut schema, 7, Attribute {
value_type: ValueType::Ref,
multival: false,
..Default::default()
});
// Scalar.
// TODO: this kind of simple `not` should be implemented without the subquery. #476.
let query = r#"[:find ?x :where [?x :db/valueType ?v] (not [(ground :db.type/instant) ?v])]"#;
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql,
"SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` WHERE `datoms00`.a = 7 AND NOT \
EXISTS (SELECT 1 WHERE `datoms00`.v = 29)");
// Coll.
// TODO: we can generate better SQL for this, too. #476.
let query = r#"[:find ?x :where [?x :db/valueType ?v] (not [(ground [:db.type/bool :db.type/instant]) [?v ...]])]"#;
let SQLQuery { sql, .. } = translate(&schema, query);
assert_eq!(sql,
"SELECT DISTINCT `datoms00`.e AS `?x` FROM `datoms` AS `datoms00` \
WHERE `datoms00`.a = 7 AND NOT EXISTS \
(SELECT 1 FROM (SELECT 0 AS `?v` WHERE 0 UNION ALL VALUES (28), (29)) AS `c00` \
WHERE `datoms00`.v = `c00`.`?v`)");
}

View file

@ -35,6 +35,7 @@ extern crate mentat_core;
use std::collections::{ use std::collections::{
BTreeSet, BTreeSet,
HashSet,
}; };
use std::fmt; use std::fmt;
@ -59,7 +60,7 @@ use mentat_core::{
pub type SrcVarName = String; // Do not include the required syntactic '$'. pub type SrcVarName = String; // Do not include the required syntactic '$'.
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord)] #[derive(Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct Variable(pub Rc<PlainSymbol>); pub struct Variable(pub Rc<PlainSymbol>);
impl Variable { impl Variable {
@ -536,21 +537,90 @@ impl FindSpec {
// Datomic accepts variable or placeholder. DataScript accepts recursive bindings. Mentat sticks // Datomic accepts variable or placeholder. DataScript accepts recursive bindings. Mentat sticks
// to the non-recursive form Datomic accepts, which is much simpler to process. // to the non-recursive form Datomic accepts, which is much simpler to process.
#[derive(Clone, Debug, Eq, PartialEq)] #[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub enum VariableOrPlaceholder { pub enum VariableOrPlaceholder {
Placeholder, Placeholder,
Variable(Variable), Variable(Variable),
} }
impl VariableOrPlaceholder {
pub fn into_var(self) -> Option<Variable> {
match self {
VariableOrPlaceholder::Placeholder => None,
VariableOrPlaceholder::Variable(var) => Some(var),
}
}
pub fn var(&self) -> Option<&Variable> {
match self {
&VariableOrPlaceholder::Placeholder => None,
&VariableOrPlaceholder::Variable(ref var) => Some(var),
}
}
}
#[derive(Clone,Debug,Eq,PartialEq)] #[derive(Clone,Debug,Eq,PartialEq)]
pub enum Binding { pub enum Binding {
BindRel(Vec<VariableOrPlaceholder>),
BindColl(Variable),
BindTuple(Vec<VariableOrPlaceholder>),
BindScalar(Variable), BindScalar(Variable),
BindColl(Variable),
BindRel(Vec<VariableOrPlaceholder>),
BindTuple(Vec<VariableOrPlaceholder>),
}
impl Binding {
/// Return each variable or `None`, in order.
pub fn variables(&self) -> Vec<Option<Variable>> {
match self {
&Binding::BindScalar(ref var) | &Binding::BindColl(ref var) => vec![Some(var.clone())],
&Binding::BindRel(ref vars) | &Binding::BindTuple(ref vars) => vars.iter().map(|x| x.var().cloned()).collect(),
}
}
/// Return `true` if no variables are bound, i.e., all binding entries are placeholders.
pub fn is_empty(&self) -> bool {
match self {
&Binding::BindScalar(_) | &Binding::BindColl(_) => false,
&Binding::BindRel(ref vars) | &Binding::BindTuple(ref vars) => vars.iter().all(|x| x.var().is_none()),
}
}
/// Return `true` if no variable is bound twice, i.e., each binding entry is either a
/// placeholder or unique.
///
/// ```
/// extern crate mentat_query;
/// use std::rc::Rc;
///
/// let v = mentat_query::Variable::from_valid_name("?foo");
/// let vv = mentat_query::VariableOrPlaceholder::Variable(v);
/// let p = mentat_query::VariableOrPlaceholder::Placeholder;
///
/// let e = mentat_query::Binding::BindTuple(vec![p.clone()]);
/// let b = mentat_query::Binding::BindTuple(vec![p.clone(), vv.clone()]);
/// let d = mentat_query::Binding::BindTuple(vec![vv.clone(), p, vv]);
/// assert!(b.is_valid()); // One var, one placeholder: OK.
/// assert!(!e.is_valid()); // Empty: not OK.
/// assert!(!d.is_valid()); // Duplicate var: not OK.
/// ```
pub fn is_valid(&self) -> bool {
match self {
&Binding::BindScalar(_) | &Binding::BindColl(_) => true,
&Binding::BindRel(ref vars) | &Binding::BindTuple(ref vars) => {
let mut acc = HashSet::<Variable>::new();
for var in vars {
if let &VariableOrPlaceholder::Variable(ref var) = var {
if !acc.insert(var.clone()) {
// It's invalid if there was an equal var already present in the set --
// i.e., we have a duplicate var.
return false;
}
}
}
// We're not valid if every place is a placeholder!
!acc.is_empty()
}
}
}
} }
// Note that the "implicit blank" rule applies. // Note that the "implicit blank" rule applies.