sqloxide 0.1.43

Python bindings for sqlparser-rs

sqloxide

---

• sqloxide
  • Installation
  • Usage
    • Parsing
    • AST Rewrites
  • Benchmarks
  • Example
  • Develop

---

sqloxide wraps rust bindings for sqlparser-rs into a python package using pyO3.

The original goal of this project was to have a very fast, efficient, and accurate SQL parser I could use for building data lineage graphs across large code bases (think hundreds of auto-generated .sql files). Most existing sql parsing approaches for python are either very slow or not accurate (especially in regards to deeply nested queries, sub-selects and/or table aliases). Looking to the rust community for support, I found the excellent sqlparser-rs crate which is quite easy to wrap in python code.

Installation

The project provides manylinux2014 wheels on pypi so it should be compatible with most linux distributions. Native wheels are also now available for OSX and Windows.

To install from pypi:

pip install sqloxide

Usage

Parsing

Parsing a SQL query is relatively straight forward:

from sqloxide import parse_sql

sql = """
SELECT employee.first_name, employee.last_name,
       call.start_time, call.end_time, call_outcome.outcome_text
FROM employee
INNER JOIN call ON call.employee_id = employee.id
INNER JOIN call_outcome ON call.call_outcome_id = call_outcome.id
ORDER BY call.start_time ASC;
"""

output = parse_sql(sql=sql, dialect='ansi')

print(output)

>>> [
  {
    "Query": {
      "ctes": [],
      "body": {
        "Select": {
          "distinct": false,
          "top": null,
          "projection": [
            {
              "UnnamedExpr": {
                "CompoundIdentifier": [
                  {
                    "value": "employee",
                    "quote_style": null
                  },
                  {
                    "value": "first_name",
                    "quote_style": null
                  }
                ]
              }
            },
            {
              "UnnamedExpr": {
                "CompoundIdentifier": [
                  {
                    "value": "employee",
                    "quote_style": null
                  },
                  {
                    "value": "last_name",
                    "quote_style": null
                  }
                ]
              }
            },
            {
              "UnnamedExpr": {
                "CompoundIdentifier": [
                  {
                    "value": "call",
                    "quote_style": null
                  },
                  {
                    "value": "start_time",
                    "quote_style": null
                  }
                ]
              }
            },
            { # OUTPUT TRUNCATED

Note that you get back what looks like a JSON document but in actual python types, this is a typed AST that matches the sqlparser-rs AST schema.

We can convert this AST back into a SQL query by running:

from sqloxide import restore_ast

query = restore_ast(ast=output)
print(query)

This reconstruction is helpful if you want to make manual edits to the AST in python.

AST Rewrites

If you want a more structured approach to AST edits, we also expose APIs that allow you to use the visitor pattern to make query modifications.

Here is an example for mutating a subset of the expressions in the query to be SHOUTING UPPERCASE:

from sqloxide import parse_sql, mutate_expressions

sql = "SELECT something from somewhere where something = 1 and something_else = 2"

def func(x):
    if "CompoundIdentifier" in x.keys():
        for y in x["CompoundIdentifier"]:
            y["value"] = y["value"].upper()
    return x

ast = parse_sql(sql=sql, dialect="ansi")
result = mutate_expressions(parsed_query=ast, func=func)
print(result)
---
>>> ['SELECT something FROM somewhere WHERE something = 1 AND something_else = 2']

What if you needed to make a structured edit to the table name in the above query? There is also an API for that as well:

from sqloxide import parse_sql, mutate_relations

def func(x):
    return x.replace("somewhere", "anywhere")
result = mutate_relations(parsed_query=ast, func=func)
print(result)
---
>>> ['SELECT something FROM anywhere WHERE something = 1 AND something_else = 2']

These features combined allow for powerful semantic rewrites of queries, if you have any examples you'd like to share please contribue back to the examples/ folder!

Benchmarks

We run 4 benchmarks, comparing to some python native sql parsing libraries:

• test_sqloxide - parse query and get a python object back from rust
• test_sqlparser - testing sqlparse, query -> AST
• test_mozsqlparser - testing moz-sql-parser, full roundtrip as in the docs, query -> JSON
• test_sqlglot - testing sqlglot, query -> AST

To run them on your machine:

poetry run pytest tests/benchmark.py

------------------------------------------------------------------------------------------- benchmark: 4 tests -------------------------------------------------------------------------------------------
Name (time in us)            Min                    Max                  Mean              StdDev                Median                 IQR            Outliers          OPS            Rounds  Iterations
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
test_sqloxide            29.6800 (1.0)          50.4300 (1.0)         30.6219 (1.0)        0.7367 (1.0)         30.4900 (1.0)        0.2390 (1.0)       527;716  32,656.3811 (1.0)        9099           1
test_sqlglot            365.8420 (12.33)       692.8950 (13.74)      377.2422 (12.32)     11.7692 (15.98)      375.7825 (12.32)      4.3145 (18.05)       62;97   2,650.8168 (0.08)       2260           1
test_sqlparser        1,577.7720 (53.16)     9,751.9699 (193.38)   1,651.5547 (53.93)    355.5511 (482.64)   1,620.7315 (53.16)     30.9200 (129.37)       3;60     605.4901 (0.02)        538           1
test_mozsqlparser     2,793.8400 (94.13)    12,358.7790 (245.07)   3,091.8519 (100.97)   960.4173 (>1000.0)  2,937.6310 (96.35)    243.3220 (>1000.0)       4;4     323.4308 (0.01)        316           1
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Example

The depgraph example reads a bunch of .sql files from disk using glob, and builds a dependency graph of all of the objects using graphviz.

poetry run python ./examples/depgraph.py --path {path/to/folder/with/queries}

Develop

1. Install rustup

2. poetry install will automatically create the venv, compile the package and install it into the venv via the build script.