ORM-SQLite

ORM-SQLite

ORM-SQLite is

• a lightweight ORM for SQLite
• written in Python (3.7+) Standard Library

Quickstart

1. Define a Pomodoro model

   import orm_sqlite  
   
   class Pomodoro(orm_sqlite.Model):  
   
       id = orm_sqlite.IntegerField(primary_key=True) # auto-increment
       task = orm_sqlite.StringField()
       interval = orm_sqlite.IntegerField()
   

2. Create a Database instance

   db = orm_sqlite.Database('example.db')
   

3. Set it as backend of Pomodoro model objects, CRUD operations thus can be performed later

   Pomodoro.objects.backend = db
   

4. Create a Pomodoro timer record (primary key is auto-increment) and insert it to backend (auto-commited)

   pomodoro = Pomodoro({'task': 'do something', 'interval': 25})
   pomodoro.save()
   

   which is equivalent to

   pomodoro = Pomodoro({'task': 'do something', 'interval': 25})
   Pomodoro.objects.add(pomodoro)   
   

5. Retrieve all the records in the backend

   Pomodoro.objects.all()
   

6. Retrieve single record by its primary key and update it (auto-commited)

   obj = Pomodoro.objects.get(pk=1)
   obj['task'] = 'do something else'
   obj.update()
   

   which is equivalent to

   obj = Pomodoro.objects.get(pk=1)
   obj['task'] = 'do something else'
   Pomodoro.objects.update(obj)
   

7. Retrieve single record by its primary key and delete it (auto-commited)

   Pomodoro.objects.get(pk=1).delete()
   

   which is equivalent to

   obj = Pomodoro.objects.get(pk=1)
   Pomodoro.objects.remove(obj)
   

8. Disconnect the backend

   Pomodoro.objects.backend.close()
   

Install ORM-SQLite

$ pip install orm-sqlite

Documentation

Module Database

class orm_sqlite.Database(database[, timeout, detect_types, isolation_level, check_same_thread, factory, cached_statements, uri])

• connected

  Instance attribute: Whether or not the SQLite database is connected.

• connection

  Instance attribute: sqlite3.Connection object

• cursor

  Instance attribute: sqlite3.Cursor object

• connect()

  Instance method: Connects the SQLite database if disconnected.

• close()

  Instance method: Disconnects the SQLite database if connected.

• select(sql, *args, size=None)

  Instance method: Returns query results, a list of sqlite3.Row objects.

• execute(sql, *args, autocommit=True)

  Instance method: Executes an SQL statement and returns rows affected.

• commit()

  Instance method: Commits the staged transaction.

Module StringField

class orm_sqlite.StringField(name=None, default='')

• name

  Instance attribute: Column name. Default: None.

• type

  Instance attribute: Column type. Default: TEXT.

• default

  Instance attribute: Column default value. Default: ''.

• primary_key

  Instance attribute: Whether or not it is the primary key. Default: False.

Module IntegerField

class orm_sqlite.IntegerField(name=None, default=0, primary_key=False)

• name

  Instance attribute: Column name. Default: None.

• type

  Instance attribute: Column type. Default: INTEGER.

• default

  Instance attribute: Column default value. Default: 0.

• primary_key

  Instance attribute: Whether or not it is the primary key. Default: False.

Module FloatField

class orm_sqlite.StringField(name=None, default=0.0)

• name

  Instance attribute: Column name. Default: None.

• type

  Instance attribute: Column type. Default: REAL.

• default

  Instance attribute: Column default value. Default: 0.0.

• primary_key

  Instance attribute: Whether or not it is the primary key. Default: False.

Module Model

class orm_sqlite.Model(*args, **kwargs)

• __table__

  Class attribute: Table.

• __mappings__

  Class attribute: Object Relational Mappings (ORMs).

• __primary_key__

  Class attribute: Primary key.

• __fields__

  Class attribute: Fields except primary key.

• objects

  Class-only attribute: orm_sqlite.Manager object used to manage corresponding Model objects.

• exists()

  Class-only method: Whether or not the table exists in the connected database.

• create()

  Class-only method: Create the table if not exists in the connected database.

• drop()

  Class-only method: Drop the table if exists in the connected database, objects.backend.commit() needed to confirm. Extremely Dangerous.

• save()

  Instance method: Inserts Model object to table in the connected database and returns rows affected (1 or -1).

• update()

  Instance method: Updates Model object from table in the connected database and returns rows affected (1 or -1). Dangerous.

• delete()

  Instance method: Deletes Model object from table in the connected database and returns rows affected (1 or -1). Dangerous.

• keys(), values(), items(), copy(), etc. methods inherited from standard dict.

Practical template for customized model:

import orm_sqlite

class MyModel(orm_sqlite.Model):

    id = orm_sqlite.IntegerField(primary_key=True) # auto-increment
    # TODO:   

Module Manager

class orm_sqlite.Manager()

• backend

  Instance attribute: orm_sqlite.Database object serving as backend of Model objects.

• all()

  Instance method: Returns all Model objects from table in the connected database.

• find(filter=None, order_by=None, **extra)

  Instance method: Returns all Model objects satified the conditions from table in the connected database.

• get(pk)

  Instance method: Returns single Model object by its primary key from table in the connected database.

• exists(pk)

  Instance method: Whether or not a primary key exists in the table from the connected database.

• aggregate(self, expression, filter=None)

  Instance method: Returns the result of an aggregate function performed on table in the connected database.

• add(obj)

  Instance method: Inserts Model object to table in the connected database and returns rows affected (1 or -1).

• update(obj)

  Instance method: Updates Model object from table in the connected database and returns rows affected (1 or -1). Dangerous.

• remove(obj)

  Instance method: Deletes Model object from table in the connected database and returns rows affected (1 or -1). Dangerous.

• clear()

  Instance method: Deletes all Model objects from table in the connected database and returns rows affected (1 or -1), backend.commit() needed to confirm. Extremely Dangerous.

Helper Function

• root_logger(log_dir='.')

  Returns root logger, a logging.logger object, logging in main module.

• child_logger(child)

  Returns child logger, a logging.logger object, logging in auxiliary module.

Related Projects

• Inspired by Django ORM