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path: root/src/clojure_sql/dsl.clj
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2013-09-29Clear up the ambiguous field error messageCarlo Zancanaro
The ambiguous field error message used to specify that it was a case where multiple tables were present, but that's not always true. If you're trying to work on a query that has been "subqueried" then you'll also get the error (arguably that should have a different error message, but I'll come back to that later).
2013-09-29Remove the `having` function, incorporate into `select`Carlo Zancanaro
The `having` function duplicated the intended functionality of `select`, but in a bad way. It only applied to a restricted case, and its existence meant that `select` provided an escape-hatch with which we could cause some unexpected behaviour. By consolidating the two functions into `select` we remove the escape hatch as well as simplify the model. Selection on grouped queries may now introduce a new subquery, but only in situations where the behaviour is unpredictable (ie. selecting on non-grouped attributes).
2013-07-12A bunch of refactoring in the DSLCarlo Zancanaro
2013-07-12Add a rename helper to turn queries into "subobjects" in the result.Carlo Zancanaro
Essentially just prefixes a subobject name in front of all fields in a query, with a dot separating the new prefix and the original name.
2013-07-06Make `sort` able to take expressions rather than just table names.Carlo Zancanaro
2013-07-03Add fields to union/intersection result queriesCarlo Zancanaro
2013-07-01Change the condition for union compatible (require projections first)Carlo Zancanaro
2013-07-01Add union/intersection to the dslCarlo Zancanaro
2013-07-01Make sure you never try to take a negative number of things!Carlo Zancanaro
2013-06-23Make sort and group create subqueries to be correctCarlo Zancanaro
2013-06-23Make select take a map and compile to equality tests.Carlo Zancanaro
2013-06-23Misc changes.Carlo Zancanaro
2013-06-21Docstrings, re-export from core better (with metadata)Carlo Zancanaro
2013-06-21Add take/drop, move jdbc stuff, document default of postgresCarlo Zancanaro
Add take and drop functionality to the queries, so now you can use the take and drop functions in a similar way to how they work on seqs in clojure. Move jdbc interface stuff into clojure-sql.jdbc, so if you're using jdbc you can include it yourself. (If you're not using jdbc then it shouldn't bother you). Given the default compilation target is actually postgres, document that.
2013-06-20A few small changes/fixes to join behaviour, and code cleanupCarlo Zancanaro
Fix compilation of cross joins. Remove the sort clauses on queries when they become subqueries in joins because then the sorting means nothing (although when take/drop stuff is added the sort will be relevant, so we'll see about that). Favour the left side of a join, which is mostly only relevant for the outer join case (and technically it's not quite right for full-outer joins, maybe, but I'll get to that later).
2013-06-17Rename sort-by, add grouping, refactor+fix some join stuffCarlo Zancanaro
`sort-by` is now called `sort`. This is just because I think it makes more sense and nothing more. Grouping has been added with `group` and `having`. They behave as you'd expect from SQL, except that joining with a table which has a `group` or `having` clause will move that query in as a subquery. I wasn't sure how else to ensure their composition, so this way maintains the semantics (which is the most important part) at the potential cost of some efficiency in performing the query. I'm not sure that there exists a more general solution. I would assume not. The join stuff has been fixed a bit (some valid renames were rejected as invalid) and standardised a bit (exceptions are now more similar). A bunch of things have been added to the join stuff as a result of the above grouping things, too. A bunch of changes all around, basically. The compiler has also had a few small changes made to it, and has been enhanced to support the grouping stuff.
2013-06-16Fix up some more join stuff, and a bit of sorting stuff.Carlo Zancanaro
2013-06-16Fix expression processing in the DSL, notably on vectorsCarlo Zancanaro
2013-06-16Bring the DSL back up to previous features, fix the compilerCarlo Zancanaro
It should generally be usable at this point. It should generate the queries correctly (including join order and stuff) and approximately properly do things. The type of join stuff still hasn't been finished, but if the code were left as-is it would still be possible to get whatever you wanted out of it, I think. Basically: lots of work has been done and we're approaching something more usable.
2013-06-13Starting a re-write of the DSL, to be followed by the compiler.Carlo Zancanaro
Flip around field/table aliases, do joins a bit differently. They're my main aims at the moment! I'll also add a preprocessor for the compiler to massage it into a nicer form there. I discovered that joins can be done with a pretty sweet syntax in SQL: (tableA LEFT JOIN tableB) RIGHT JOIN tableC This is pretty much perfect for my purposes. Flipping alias maps just makes more sense and removes a whole bunch of `flip-map` calls that would be unnecessary if the aliases were the other way around. The user-facing side of the DSL will be left unchanged, though. The user provides an `{old-name new-name}` map and internally we convert that into `{new-name old-name}`. Like magic. I'm also adding a bunch more tests. Hopefully that will make things more likely to work for long periods of time. Peace out!
2013-05-24Fix a bug in `resolve-fields`Carlo Zancanaro
The recursive calls to `resolve-fields` were not being made due to programmer error. This has been fixed, so now the field resolution stuff should work properly again. This is really highlighting the need for better testing. Get on that!
2013-05-23Simplify the compiler, better subquery supportCarlo Zancanaro
The compiler's been simplified a bit by breaking out the `writer` stuff into its own namespace and by generally making the monadic stuff better. It's all hidden behind a nice, simple, `clojure-sql.compiler/compile` function now. Call that and you'll get back what you need. (Internally it's a writer monad which is really modelled as a state monad with the only operation able to be performed on the state being `tell`.) Subqueries are now handled by the DSL in such a way as to not blow up everything. Subqueries have no support for referencing values in the superquery, though, so their utility is quite limited at present. Thinking about how to do subqueries properly may be difficult.
2013-05-15Split out core into compiler/dsl/query.Carlo Zancanaro
The query namespace really only exists because I didn't want to put it in dsl, but I couldn't put it in core without a circular dependency. Users should only have to :require core to do things, though. It just aliases other stuff to make that work.