Querify

A simple query generator from filter conditions in form of json.

This package aims to represent a database query with a unified form of json structure, so that it can be converted to MySQL / Mongo / InfluxQL / Pandas queries any time when necessary. The json structure is very much like mongodb query objects, making it easy to pick up quickly for users that have relevant experience.

Installation

pip install querify

Note: Only works for python 3.

Usage

Before all it starts, let's import the Expr class.

>>> from querify import Expr

To build a query expression object, simply call its from_json method with a json object:

>>> expr = Expr.from_json({"a": {"__gt__": 5}})

then you can convert it to any form you want:

>>> expr.to_query('mysql')
'a > 5'

>>> expr.to_query('influx')
'"a" > 5'

>>> expr.to_query('mongo')
{'a': {'$gt': 5}} 

>>> expr.to_query('pandas')
'a > 5'

>>> expr.to_query('pluto')
'a is more than 5'

Supported Operators

• __eq__
  Assert that a variable is equal to a value. e.g. {a: {__eq__: 5}} (Abbreviation: {a: 5})

• __neq__
  Assert that a variable is equal to a value. e.g. {a: {__neq__: "some_str_value"}}

• __gt__
  Assert that a variable is larger than a value. e.g. {a: {__gt__: 5}}

• __gte__
  Assert that a variable is larger than or equal to a value. e.g. {a: {__gte__: 5}}

• __lt__
  Assert that a variable is smaller than a value. e.g. {a: {__lt__: 5}}

• __lte__
  Assert that a variable is smaller than or equal to a value. e.g. {a: {__lte__: 5}}

• __regex__
  Assert that a variable matches a regular expression. e.g. {a: {__regex__: "^[a-z0-9_-]{3,16}$"}} (Abbreviation: {a: "/^[a-z0-9_-]{3,16}$/"})

• __iregex__
  Assert that a variable does not match a regular expression. e.g. {a: {__iregex__: "^[a-z0-9_-]{3,16}$"}}

• __null__
  Assert that a variable is null or not. e.g. {a: {__null__: true}}

• __in__
  Assert that a variable's value equals to one of the values in a list. e.g. {a: {__in__: ["A", "B"]}} (Abbreviation: {a: ["A", "B"]})

• __nin__
  Assert that a variable's value does not equal to any of the values in a list. e.g. {a: {__nin__: ["A", "B"]}}

• __and__ or __all__
  Assert that the expression holds when all of the sub-expressions in the list are true.
  e.g. {__and__: [{a: {__gt__: 5}}, {b: {__neq__: "B"}}]} (Abbreviation: {a: {__gt__: 5}, b: {__neq__: "B"}})

• __or__ or __any__
  Assert that the expression holds if any of the sub-expressions in the list is true.
  e.g. {__or__: [{a: {__gt__: 5}}, {b: {__neq__: "B"}}]}

• __not__
  Assert that the expression holds if the sub-expressions is false.
  e.g. {__not__: {a: {__gt__: 5}} (Equivalence: {a: {__lte__: 5})

Advanced Usage

The code should be pretty much self-explanatory. Please refer to the test cases in the repo and see if something interests you. :)

BTW, welcome for any PRs that make this package more powerful!

Authors

• Raychee - Initial work - Querify
• Rambo - Operators Extension
• Qianwen - Operators Extension

License

This project is licensed under the MIT License - see the LICENSE file for details.