sqlitemodel 0.1.3

Wrapper for the sqlite3 database that enables you to create models you can easily query, save and update.

sqlitemodel is a wrapper for the sqlite3 database that enables you to create models you can easily save, query and retrieve from the database.

This is build with three classes who abstract the database communication and the object management.

Installation

Install through pip.

$ pip install sqlitemodel

or get from source

$ git clone https://github.com/gravmatt/sqlitemodel.git
$ cd sqlitemodel
$ python setup.py install

Classes

• **Model** - Abstraction class to build database models

• **SQL** - SQL query builder

• **Database** - sqlite database interface

Model

Class to abstract the model communication with the database.

Usage

Import

from sqlitemodel import Model, Database

# IMPORTANT
Database.DB_FILE = 'path/to/database.db'

Set the path to the database when your application starts or before you try to accessing the database.

Example

Building a user class that inherits the Model class to show how it works.

class User(Model):
    def __init__(self, id=None):
        Model.__init__(self, id, dbfile=None, foreign_keys=False, parse_decltypes=False)

        self.firstname = ''
        self.lastname = ''
        self.age = ''

        # Tries to fetch the object by its rowid from the database
        self.getModel()


    # Tells the database class the name of the database table
    def tablename(self):
        return 'users'


    # Tells the database class more about the table columns in the database
    def columns(self):
        return [
            {
              'name': 'firstname',
              'type': 'TEXT'
            },
            {
              'name': 'lastname',
              'type': 'TEXT'
            },
            {
              'name': 'age',
              'type': 'INTEGER'
            }
        ]

The two methods tablename() and columns() are required, to map the table columns with the Model objects.

id argument and the getModel() method in the constructor are optional.

It also possible to use the selectCopy() method to query for any data in the database table and fill the model object with the result.

selectCopy(SQL() | raw_sql_query_string)

Ex:

class User(Model):
    def __init__(self, id=None, email=None):
        Model.__init__(self, id)
        if(email):
            self.selectCopy(SQL().WHERE('email', '=', email))

The ``Model`` class constructor has an optional ``dbfile`` argument. If it is set, the static variable ``Database.DB_FILE`` is ignored.

Working with the User class

Creating a new User

# create a new user
user = User()

# creating the table inside the database
user.createTable()

# add infos about the user
user.firstname = 'Rene'
user.lastname = 'Tanczos'
user.age = 25

# save the user into the database
user.save()

Retriving the User from the database

# get it by id
user = User(1)

# get the user by his firstname and lastname
# User().selectOne(SQL())
user = User().selectOne(SQL().WHERE('firstname', '=', 'Rene').AND().WHERE( 'lastname', '=', 'Tanczos'))

# Or get more the one user
# this method will return an array of matching users
users = User().select(SQL().WHERE('age', '=', 25))

SQL

Class to build SQL query to reduce misspelling and to abstract this problem a bit.

Usage

Import

from sqlitemodel import SQL

INSERT

sql = SQL().INSERT('users').VALUES(firstname='Rene', lastname='tanczos')

print sql.toStr()
# INSERT INTO users (firstname,lastname) VALUES (?,?);

print sql.getValues()
# ('Rene', 'tanczos')

UPDATE

sql = SQL().UPDATE('users').SET('firstname', 'Rene').SET('lastname', 'Tanczos').WHERE('firstname', '=', 'Rene').AND().WHERE('lastname', '=', 'Tanczos')

print sql.toStr()
# UPDATE users SET firstname=?, lastname=? WHERE firstname=? AND lastname=?;

print sql.getValues()
# ('Rene', 'Tanczos', 'Rene', 'Tanczos')

SELECT

sql = SQL().SELECT('name', 'age', 'size').FROM('users').WHERE('age', '=', 27).AND().WHERE('size', '<', 190).ORDER_BY('age', 'ASC').LIMIT(0, 10)

print sql.toStr()
# SELECT name, age, size FROM users WHERE age=? AND size<? ORDER BY age ASC LIMIT 0,10;

print sql.getValues()
# (27, 190)

WHERE

The WHERE method has a optional isRaw parameter.

If set to True, the SQL class paste the value directly into the sql query and does not use the ? symbol.

WHERE('size', '<', 190, isRaw=True)

DELETE

sql = SQL().DELETE('users').WHERE('id', '=', 4)

print sql.toStr()
# DELETE FROM users WHERE id=?;

print sql.values
# (4,)

Database

Represents the database.

Usage

First you should set the database file path to your sqlite3 database.

Don’t worry if it doesn’t exist yet. Sqlite3 automatically creates a database file on the selected path if it doesn’t exists.

from sqlitemodel import Database

Set the path to the database

It is recommended to set the path to the database after starting the application by the static variable inside the Database class.

Database.DB_FILE = 'path/to/database.db'

db = Database()

But the path can be also set inside the Database constructor while the object initializes.

db = Database('path/to/database.db')

with statement

The Database class supports the with statement whitch is recommended to use.

with Database() as db:
    users = db.select(SQL().SELECT().FROM('users'))

The database connection get automatically closed after the with block is processed.

Methods

All of this method using a Model object as first argument, so that the Database object knows how to use it.

close()
# close connection

createTable(model)
# create the database table if not exists by the the model object

save(model)
# create or update a model object and return it id

delete(model)
# delete a model object and return True/False

select(model, SQL() | sql query , values=())
# return a array of the given model

selectOne(model, SQL() | sql query, values=())
# return the first matching entry of the given model

selectById(model, id)
# return the a model object by his id

If there is some data without a Model, it can be retrieved as raw data of a list or list of Dict objects.

getRaw(SQL() | sql query, values=(), max=-1)
# return an array of results.
# index 0 is the header of the table

getDict(SQL() | sql query, values=(), max=-1)
# return a list array with a Dict object.
# the key of the Dict object is the column name

To count the results of a query, the method zeroZero() can be used.

zeroZero(SQL() | sql query)
# It return the the first column of the first line ( result[0][0] )
# That why the method is called zeroZero()

To check if a table or column exists, the functions table_exists() and column_exists() can be used. Both will return a boolean value if the table/column was found or not.

table_exists('tablename')
# True or False

column_exists('tablename', 'column_name')
# True or False

Licence

The MIT License (MIT)

Copyright (c) 2016-2017 René Tanczos

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.