Commit graph

10 commits

Author SHA1 Message Date
Richard Newman
bc63744aba Add :limit to queries (#420) r=nalexander
* Pre: put query parts in alphabetical order.
* Pre: rename 'input' to 'query' in translate tests.
* Part 1: parse :limit.
* Part 2: validate and escape variable parameters in SQL.
* Part 3: algebrize and translate limits.
2017-04-19 16:16:19 -07:00
Richard Newman
35d73d5541 Implement :order. (#415) (#416) r=nalexander
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.
2017-04-17 11:30:31 -07:00
Richard Newman
08d2c613a4 Part 2: expand the definition of a table to include computed tables.
This commit:

- Defines a new kind of column, distinct from the eavt columns in
  `DatomsColumn`, to model the rows projected from subqueries. These
  always name one of two things: a variable, or a variable's type tag.
  Naturally the two cases are thus `Variable` and `VariableTypeTag`.
  These are cheap to clone, given that `Variable` is an `Rc<String>`.
- Defines `Column` as a wrapper around `DatomsColumn` and
  `VariableColumn`. Everywhere we used to use `DatomsColumn` we now
  allow `Column`: particularly in constraints and projections.
- Broadens the definition of a table list in the intermediate
  "query-sql" representation to include a SQL UNION. A UNION is
  represented as a list of queries and an alias.
- Implements translation from a `ComputedTable` to the query-sql
  representation. In this commit we only project vars, not type tags.

Review comment: discuss bind_column_to_var for ValueTypeTag.
Review comment: implement From<Vec<T>> for ConsumableVec<T>.
2017-04-12 19:21:33 -07:00
Richard Newman
997df0b776 Part 1: introduce ColumnIntersection and ColumnAlternation.
This provides a limited form of OR and AND for column constraints, allowing
simple 'or-join' queries to be expressed on a single table alias.
2017-03-30 19:13:19 -07:00
Richard Newman
88df7b3b33 Correctly generate DISTINCT and LIMIT. (#386) r=nalexander 2017-03-22 14:02:00 -07:00
Richard Newman
97749833d0 Algebrize and translate numeric constraints. (#306) r=nalexander 2017-03-22 10:19:47 -07:00
Richard Newman
bf38105fef (#362) Part 4: handle unknown attributes by expanding type codes. r=nalexander
Also, don't run any SQL at all if an algebrized query is known to return no results.
2017-03-08 17:44:27 -08:00
Richard Newman
1961815acd Pre: add an interpose macro for SQL output. 2017-03-08 17:41:50 -08:00
Richard Newman
e898df8842 Implement basic query limits. (#361) r=nalexander 2017-03-08 17:41:42 -08:00
Richard Newman
70b112801c Implement projection and querying. (#353) r=nalexander
* Add a failing test for EDN parsing '…'.
* Expose a SQLValueType trait to get value_type_tag values out of a ValueType.
* Add accessors to FindSpec.
* Implement querying.
* Implement rudimentary projection.
* Export mentat_db::new_connection.
* Export symbols from mentat.
* Add rudimentary end-to-end query tests.
2017-03-06 14:40:10 -08:00