Django-Marathon 2/6

Django Vs ___________ ?

• MVC: Asp.net MVC 
• Django create forms in predefined form layout and need tweak to modify
• Routing is done by controller in asp.net in Django do using expression 

Create Project using Django-Admin :

>>>django-admin startproject app-name folder-name
>>>django-admin startapp app theapp // theapp is name of folder
\\Add  app created in  settings.py

What  is Model  : MVC controller Diagram ?

•                                 Data : regarding data as per projects 
•                                 Model  : Class  for project , prevent sql injection attacks if using models

ORM:. Object relational mapping 

• -          Converts queries into SQL 
• -          Converts results into objects 

Implementation of ORM

• -          Hibernate in Java
• -          Entity Framework in LINQ 
• -          Django

>> Save , Delete & Update queries are managed by Django Framework contained in (models.Model)

>> Properties: size,datatype,Nullability 

-          Syntax property_name=models.Type(parameters)

-           Eg name=models.IntegerField(null/default/blank/max_length)

Primary Key is added automatically else : 

Foreign Key  Syntax

                Artist=models.ForiegnKey(Artist) // Automatically map columns to  object 

• Use (name_name instead of nameNAme ) for models to help out  in Autogenerated forms

For field options in Django  : https://docs.djangoproject.com/en/1.10/ref/models/fields/

What database Django Support  ?

• -          SQLite (default in settings.py)
• -          MySQL
• -          Microsoft SQL Server

How to create Database  ?

• -          Makemigrations : create package and send to database 
• -          Sqlmigrate : display sql statement done by migrate
• -          Migrate: take the package and create database 

Command for Migration 

-          python manage.py makemigration  --name migration_name  app

-          python manage.py showmigrations app  [to show all migrations done yet  ]

-          python manage.py sqlmigrate app  0001_initial  [to sql command generated ]

-          python manage.py migrate

-          python manage.py app  migrate app 0001_initial