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Description:

picorm 0.1.5

picorm

Picorm is a small ORM with limited functions for multiple database engines for pet-projects, mostly for simple CRUD operations in cases, when you don't want to introduce a solid ORM like SQLAlchemy or whatever, but still want to keep storage-related stuff out of your code.
Getting Started
Installation
To install from pypi:
pip install picorm

Simple usage
from collections import OrderedDict
from picorm import FileStorage as Storage # import one of storage implementations

storage = Storage('path_to_database_file') # create storage object

# every collection that you need to store must inherit from storage's Table class
class Users(storage.Table):
def __init__(self, fields = {}):
defaults = OrderedDict([('key', 'users')]) # specify table name
for k, v in fields.items():
defaults[k] = v
super().__init__(defaults)
storage.create('users', OrderedDict([ # specify table name and desired fields to be stored
('key', storage.types['int']),
('id', storage.types['int']),
('name', storage.types['str']),
('type', storage.types['str']),
]))
# every query on storage.users will return object of this class if not specified otherwise
class User(self.Record):
def __init__(self, fields = {}):
# default values for fields
defaults = OrderedDict([
('key', -1),
('id', -1),
('name', ':null'),
('type', ':null'),
])
for k, v in fields.items():
defaults[k] = v
super().__init__(defaults)
# that's it, you can add your own methods and properties
self.User = User # attach classes to table object
users = Users() # create table object
users.Record = users.User # make every query return object of class User

Storage querying
new_user = users.User({'id': 42, 'name': 'foo'}) # create record, you can do it this way or through storage.users.User
users.add (new_user) # place it in storage
found_user = users.find_one({'name': 'foo'}) # get storage Record - an object of class User
found_user.get('id') # get record's field value
found_user.set({'name': 'bar'}) # change desired fields
storage.disconnect() # don't forget to disconnect from storage if you're planning to switch engines

Return different subclasses of table record
In those cases, when you need queries to return various subclasses of table record, you can simply introduce them after User definition in example:
class Users(storage.Table):
def __init__(self, fields = {}):
# ...
class Player(User): # an example of subclassing table Record
type = 'player'
def __init__(self, fields):
overrides = {'type': Player.type}
merged = {**fields, **overrides}
super().__init__(merged)

# ...
self.Player = Player # attach class to table object

# create a type -> class map to return objects of different subclasses of table record
self.type_class_map = {
Player.type: Player,
User.type: User,
':null': User, # "default" class to wrap record
}

# make every query return object of either Player or User class based on "type" field value
users.Record = lambda fields: users.type_class_map[fields['type']](fields)

Table methods

method
arguments
returns

create
self, name, schema, log
None

find
self, selector
list of Record objects

find_one
self, selector
Record object or None

find_max
self, key
Record object or None

add
self, record
None

remove
self, record
None

Record operations

method
arguments
returns

set
self, fields
None

get
self, key
Record's field value

Supported engines

File storage
SQLite storage

Development
Environment setup

Install Python 3.9+
Install virtualenv
pip install virtualenv

Clone this project
From project directory, run
virtualenv .env

Note: This will create a virtual environment using the Python version
that virtualenv was run with (which will be the version it was installed
with). To use a specific Python version, run:
virtualenv --python=<path_to_other_python_version> .env
# For example, this might look like
virtualenv --python=/usr/bin/python3.6 .env

Assuming you are using the bash shell, run:
source .env/bin/activate

For other shells, see the other activate.* scripts in the .env/bin/
directory. If you are on Windows, run:
.env\Scripts\activate.bat

Install all of the required packages using
pip install -r requirements.txt

Testing
This project uses tox -> pytest. To trigger tests either run tox or pytest optionally with -vv and -s flags for verbosity and prints.
Packaging module
Run the following command to package picorm module:
python -m pip install --upgrade build
python -m build

Generated archive and .whl package will be placed in dist directory.
Contributions
PR are always welcome!