cc03f5c89d
Add support for literals in the SELECT clause. This allows
SELECT fn(column, 4) or SELECT fn(column, ?).
Note, "SELECT 7 FROM tab" becomes valid in the grammar, but is still
not accepted because of failed type inference - we cannot infer the
type of 7, and don't have a favored type for literals (like C favors
int). We might relax this later.
In the WHERE clause, and Cassandra in the SELECT clause, type hints
can also resolve type ambiguity: (bigint)7 or (text)?. But this is
deferred to a later patch.
A few changes to the grammar are needed on top of adding a `value`
alternative to `unaliasedSelector`:
- vectorSimilarityArg gained access to `value` via `unaliasedSelector`,
so it loses that alternate to avoid ambiguity. We may drop
`vectorSimilarityArg` later.
- COUNT(1) became ambiguous via the general function path (since
function arguments can now be literals), so we remove this case
from the COUNT special cases, remaining with count(*).
- SELECT JSON and SELECT DISTINCT became "ambiguous enough" for
ANTLR to complain, though as far as I can tell `value` does not
add real ambiguity. The solution is to commit early (via "=>") to
a parsing path.
Due to the loss of count(1) recognition in the parser, we have to
special-case it in prepare. We may relax it to count any expression
later, like modern Cassandra and SQL.
Testing is awkward because of the type inference problem in top-level.
We test via the set_intersection() function and via lua functions.
Example:
```
cqlsh> CREATE FUNCTION ks.sum(a int, b int) RETURNS NULL ON NULL INPUT RETURNS int LANGUAGE LUA AS 'return a + b';
cqlsh> SELECT ks.sum(1, 2) FROM system.local;
ks.sum(1, 2)
--------------
3
(1 rows)
cqlsh>
```
(There are no suitable system functions!)
Fixes https://scylladb.atlassian.net/browse/SCYLLADB-296
Closes scylladb/scylladb#28256
ScyllaDB Documentation
This repository contains the source files for ScyllaDB documentation.
- The
devfolder contains developer-oriented documentation related to the ScyllaDB code base. It is not published and is only available via GitHub. - All other folders and files contain user-oriented documentation related to ScyllaDB and are sources for docs.scylladb.com/manual.
To report a documentation bug or suggest an improvement, open an issue in GitHub issues for this project.
To contribute to the documentation, open a GitHub pull request.
Key Guidelines for Contributors
- The user documentation is written in reStructuredText (RST) - a plaintext markup language similar to Markdown. If you're not familiar with RST, see ScyllaDB RST Examples.
- The developer documentation is written in Markdown. See Basic Markdown Syntax for reference.
- Follow the ScyllaDB Style Guide.
To prevent the build from failing:
-
If you add a new file, ensure it's added to an appropriate toctree, for example:
.. toctree:: :maxdepth: 2 :hidden: Page X </folder1/article1> Page Y </folder1/article2> Your New Page </folder1/your-new-article> -
Make sure the link syntax is correct. See the guidelines on creating links
-
Make sure the section headings are correct. See the guidelines on creating headings Note that the markup must be at least as long as the text in the heading. For example:
---------------------- Prerequisites ----------------------
Building User Documentation
Prerequisites
- Python
- poetry
- make
See the ScyllaDB Sphinx Theme prerequisites to check which versions of the above are currently required.
Mac OS X
You must have a working Homebrew in order to install the needed tools.
You also need the standard utility make.
Check if you have these two items with the following commands:
brew help
make -h
Linux Distributions
Building the user docs should work out of the box on most Linux distributions.
Windows
Use "Bash on Ubuntu on Windows" for the same tools and capabilities as on Linux distributions.
Building the Docs
- Run
make previewin thedocs/directory to build the documentation. - Preview the built documentation locally at http://127.0.0.1:5500/.
Cleanup
You can clean up all the build products and auto-installed Python stuff with:
make pristine
Information for Contributors
If you are interested in contributing to Scylla docs, please read the Scylla open source page at http://www.scylladb.com/opensource/ and complete a Scylla contributor agreement if needed. We can only accept documentation pull requests if we have a contributor agreement on file for you.
Third-party Documentation
-
Do any copying as a separate commit. Always commit an unmodified version first and then do any editing in a separate commit.
-
We already have a copy of the Apache license in our tree, so you do not need to commit a copy of the license.
-
Include the copyright header from the source file in the edited version. If you are copying an Apache Cassandra document with no copyright header, use:
This document includes material from Apache Cassandra.
Apache Cassandra is Copyright 2009-2014 The Apache Software Foundation.