JSONField for MySQL Peewee library

This package is a JSONField on steroids for use with ORM Peewee, adding functions for working with NoSQL data (JSON fields)

By default, in Peewee, JSONField is a simple field inherited from TextField without any settings and additional methods, however, in MySQL/MariaDB there are many methods for working with JSON data that are either not used or need to be implemented yourself. This package is designed to fix this situation.

Installation

pip install peewee-jsonfield

Using

Suppose you have a table with a JSON type field, for example:

class TestModel(Model):
    id: int | AutoField = AutoField()
    data: dict | JSONField = JSONField()

With this library, you can use the SQL method JSON_SET using a simple python-specific syntax:

# Adding an integer variable to the "data" root
TestModel.data.jset('$.v_integer_key', 10).where(TestModel.id == 1).execute()

# Adding an dict variable to the "data" root
query: ModelUpdate = TestModel.data.jset('$.v_dict_key', {'nested1': 10})
query = query.where(TestModel.id == 1)
# ... any other where
query.execute()

You can use SQL method JSON_MERGE_PATCH to add nested variables in dict:

# Adding an nested dict variable to the root.v_dict_key
TestModel.data.jset('$.v_dict_key.nested_variable', 'nested_string').where(TestModel.id == 1).execute()

# Adding an nested list variable to the root.v_dict_key
TestModel.data.jset('$.v_dict_key.nested_list', [1, 2, 3]).where(TestModel.id == 1).execute()

You can use the SQL method JSON_EXTRACT to filter the results:

obj = TestModel.get_or_none(TestModel.data.jextract('$.v_str') == 'my_new_string')
objs = TestModel.select().where(TestModel.data.jextract('$.v_int') == 10)

Also, if you already have an object, instead of completely overwriting (.save()), you can use the UPDATE functions, specifying it as target and execute=True if the request needs to be executed immediately:

obj: TestModel = TestModel.get(TestModel.id == 1)
# some reading code
TestModel.data.jset('$.v_integer_key', 30, target=obj, execute=True)
TestModel.data.jset('$.v_string_key', 'testing new library', target=obj, execute=True)

To remove fields from a JSON field, you can use the .jremove() method:

TestModel.data.jremove('$.v_integer_key', target=obj, execute=True)
TestModel.data.jremove('$.v_dict_key.nested1', target=obj, execute=True)

# Query without WHERE
TestModel.data.jremove('$.v_string_key', execute=True)

Additional options

This field can also take additional options from the dbhandle object:

• dbhandle.json_ensure_ascii = True - setting the ensure_ascii parameter in the json library when saving data to the database
• dbhandle.json_use_detailed = False - setting the indent=2 parameter in the json library and using the intermediate SQL formatting function JSON_DETAILED when saving data to the database

More examples and try

View and run the file jsonfield_play.py

Before starting, you need to set environment variables to access the database: db_name, db_user, db_passwd and others (db_host, db_port, opt_table_temporary, opt_json_ensure_ascii, opt_json_use_detailed) as needed

TODO

• Implement arrays methods
• Add method's description
• Add basic jpath checks

Limitations

This library is focused on working with MariaDB and MySQL DBMS and, most likely, will not work with others, since the syntax of SQL functions differs

To use the target parameter, the table must have a row ID with the name id