cratedb-sqlparse

Antlr4 is a parser generator for reading, processing and executing text, there are several target languages (Java, Python, JavaScript, Dart...) available. CrateDB uses the Java target.

The repository holds libraries/packages created from some of those available languages, so far: Python and JavaScript. More might be added if needed in the future.

These libraries allow you to parse Crate's SQL dialect without sending it to a CrateDB instance.

• Python: https://github.com/crate/cratedb-sqlparse/tree/master/cratedb_sqlparse_py
• Javascript: https://github.com/crate/cratedb-sqlparse/tree/master/cratedb_sqlparse_js

Example:

from cratedb_sqlparse import sqlparse

query = """
    SELECT * FROM SYS.SHARDS;
    INSERT INTO doc.tbl VALUES (1);
"""
statements = sqlparse(query)

select_query = statements[0]

print(select_query.query)
# 'SELECT * FROM SYS.SHARDS'

Limitations

Listeners are not implemented, which means that you can only: Validate SQL syntax, split queries and get some Tokens metadata from the query, if you need some more information like what https://github.com/macbre/sql-metadata does ( e.g. get the columns of this query) open a new issue.

New features should preferably be implemented in all available targets.

Adding a new target

The target language has to be available in antlr4, see https://github.com/antlr/antlr4/blob/master/doc/targets.md.

Add the new target and paths to the build script, see setup_grammar.py.

There are several features that would need to be implemented, like case-insensitive input stream, native exceptions as error listener, dollar strings and any new one. See past commits to see how they were implemented in Python and Javascript, remember that CrateDB's SQLParser written in Java is the most complete and the default reference.

Building locally & using a different CrateDB version.

The generated parser is not uploaded to the repository since it's huge, to use the package locally or to build a different version use the build script.

Clone the project

git clone [email protected]:crate/cratedb-sqlparse.git

Install the dependencies

pip install antlr4-python3-runtime requests

Run the build script

python3 setup_grammar.py

At the end of the build script setup_grammar.py the target and the CrateDB version can be modified.

if __name__ == '__main__':
   version = '5.6.4'
   target = Antlr4Target.python
   download_cratedb_grammar(version)
   compile_grammar(target)
   patch_lexer(target)
   set_version(target, version)