diff --git a/README.md b/README.md
new file mode 100644
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@@ -0,0 +1,5 @@
+# Object-Relational Mapping Examples
+
+In this repository are available some easy Object-Relational Mapping (ORM) examples.
+
+For more details, please refer to the _Lecture 6 – Data Model Implementation_ of the _Open Data Management & the Cloud_ course.
diff --git a/django_example/README.md b/django_example/README.md
new file mode 100644
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+# Django Example
+
+Create the anaconda environment for this example
+
+ conda create -n insurance django
+
+To activate this environment, use
+
+ conda activate insurance
+
+Additional packages are needed, not available in Anaconda but installed with the `pip` command
+
+ pip install django-extensions djangorestframework
+ pip install django-composite-field django-url-filter
+ pip install django-phonenumber-field phonenumbers
+ pip install Pillow
+
+To deactivate an active environment, use
+
+ conda deactivate
+
+## Create a Django Project
+
+Run the following commands
+
+ django-admin startproject insurance
+ cd insurance
+ python manage.py startapp insurancedb
+
+which create a project folder, named insurance, with additional files and then an application, named insurancedb, inside the project.
+It automatically creates skeleton files needed by a Django project and application.
+
+Copy the `admin.py` and `models.py` files to the `insurancedb` folder
+
+ cp ../admin.py insurancedb/
+ cp ../models.py insurancedb/
+
+and copy the `urls.py` and `views.py` file to the `insurance` folder
+
+ cp ../urls.py insurance/
+ cp ../views.py insurance/
+
+Edit the `insurance/setting.py` file adding in the `INSTALLED_APPS` list
+two more elements: `django_extensions` and `insurancedb`. Then your
+application definition should appear like this
+
+ INSTALLED_APPS = [
+ 'django.contrib.admin',
+ 'django.contrib.auth',
+ 'django.contrib.contenttypes',
+ 'django.contrib.sessions',
+ 'django.contrib.messages',
+ 'django.contrib.staticfiles',
+ 'django_extensions',
+ 'insurancedb',
+ ]
+
+Finally, generate a migration and migrate
+
+ python manage.py makemigrations
+ python manage.py migrate
+
+Insert some data
+
+ python manage.py shell < ../insert.py
+
+Create an admin user
+
+ python manage.py createsuperuser
+
+Run the Django web server
+
+ python manage.py runserver
+
+Access to <http://127.0.0.1:8000>.
diff --git a/euclid_example/README.md b/euclid_example/README.md
index ec2f30294bfc943b56383001cfc89a7e50b8f6ac..256a0db9a1b1257772e915179c3244ebfafd2ee8 100644
--- a/euclid_example/README.md
+++ b/euclid_example/README.md
@@ -1,33 +1,39 @@
# ORM Example - Euclid
- git clone https://www.ict.inaf.it/gitlab/odmc/orm_example.git
- cd orm_example/euclid_example
+Create the anaconda environment for this example
-Crea l'ambiente di anaconda
+ conda create -n euclid_example django
+
+To activate this environment, use
- conda create -n euclid_example
conda activate euclid_example
- pip install django-extensions djangorestframework django-composite-field django-url-filter
-python manage.py migrate
+Additional packages are needed, not available in Anaconda but installed with the `pip` command
+
+ pip install django-extensions djangorestframework
+ pip install django-composite-field django-url-filter
+
+To deactivate an active environment, use
+
+ conda deactivate
+
-python manage.py shell
+## Run the Django Project
-python manage.py runserver
+Apply migrations
-add admin password
+ python manage.py migrate
+Create an admin user
-## Start from scratch
+ python manage.py createsuperuser
- django-admin startproject euclid_example
- cd euclid_example
- python manage.py startapp imagedb
+You can access the database throught the Django shell
-Also in settings.py you have to add the name of the app imagedb
+ python manage.py shell
-In the imagedb/models.py add the data model classes
+or running the Django web server
-Once we have defined our data model in imagedb/models.py we need Django to create the corresponding DB schema
+ python manage.py runserver
-python manage.py makemigrations
+then access to <http://127.0.0.1:8000/admin>.
diff --git a/sqlalchemy_example/README.md b/sqlalchemy_example/README.md
index 0fb1f1e09208b53f90c6201cf91810ca248c4e04..fff7165b1953ab6c14c44614bf8254460f834d91 100644
--- a/sqlalchemy_example/README.md
+++ b/sqlalchemy_example/README.md
@@ -1,14 +1,122 @@
+# SQLAlchmy Examples
Create the anaconda environment for this set of examples
conda create -n orm_sqlalchemy sqlalchemy
-## # To activate this environment, use
-#
-# $ conda activate orm_sqlalchemy
-#
-# To deactivate an active environment, use
-#
-# $ conda deactivate
+To activate this environment, use
+ conda activate orm_sqlalchemy
+To deactivate an active environment, use
+
+ conda deactivate
+
+
+## Example 1
+
+In this first example we are going to map a single _Car_ table.
+Each _Car_ has an integer _id_ as primary key, a _name_ and a _price_.
+
+Enter the `example_1` directory
+
+ cd example_1
+
+All the SQLAlchmy components
+(engine, declarative base class, mapping and session class)
+are configured in the `mapping.py` file.
+
+Create the database
+
+ python create.py
+
+the SQLite file `example_1.db` has been created.
+Now insert some data
+
+ python insert.py
+
+Select all data in the database
+
+ python read.py
+
+and perform some queries filtered by car name, by id or by car price
+
+ python filter.py
+
+Exit from the example_1 directory
+
+ cd ..
+
+
+## Example 2
+
+In this second example we are going to map two tables, _Author_ and _Book_,
+connected with a one-to-many relation.
+Each _Author_ has an integer _id_ as primary key and a _name_.
+Eack _Book_ has an integer _id_ as primary key, a _title_ and an *author_id* as foreign key.
+
+Enter the `example_2` directory
+
+ cd example_2
+
+All the SQLAlchmy components
+(engine, declarative base class, mapping, relationship and session class)
+are configured in the `mapping.py` file.
+
+Create the database
+
+ python create.py
+
+the SQLite file `example_2.db` has been created.
+Now insert some data
+
+ python insert.py
+
+Perform some queries selecting all books by an author or a book to get its author
+
+ python filter.py
+
+Exit from the example_2 directory
+
+ cd ..
+
+**WARNING**
+In SQLite you have to enable foreign key constraint executing
+
+ PRAGMA foreign_keys=ON;
+
+
+## Example 3
+
+In this third example we are going to map inheritance with three tables, _Client_, _Person_ and _Company_, where a _Client_ can be a _Person_ or a _Company_.
+
+Each _Client_ has an integer _id_ as primary key, an _address_ and a _type_.
+Each _Person_ has an integer _id_ as primary foreign key, a _name_ and a _surname_.
+Each _Company_ has an integer _id_ as primary foreign key, a _company_name_ and a _industry_.
+
+The _type_ discriminates if the _Client_ is also a _Person_ or a _Company_. The _id_ is unique among _Client_, _Person_ and _Company_.
+
+Enter the `example_3` directory
+
+ cd example_3
+
+All the SQLAlchmy components
+(engine, declarative base class, mapping, relationship and session class)
+are configured in the `mapping.py` file.
+
+Create the database
+
+ python create.py
+
+the SQLite file `example_3.db` has been created.
+Now insert some data
+
+ python insert.py
+
+Perform some queries selecting all clients by address or only clients which are persons by address
+
+ python filter.py
+
+Exit from the example_3 directory
+
+ cd ..
diff --git a/sqlalchemy_example/example_2/mapping.py b/sqlalchemy_example/example_2/mapping.py
index ab9f931dc18460c289cfe1bf3b884fe79ccf2c3b..fc869f8b7ef29254370b890647a659c6b736c658 100644
--- a/sqlalchemy_example/example_2/mapping.py
+++ b/sqlalchemy_example/example_2/mapping.py
@@ -28,7 +28,7 @@ class Book(Base):
id = Column(Integer, primary_key=True)
title = Column(String)
- author_id = Column(Integer, ForeignKey("Author.id"))
+ author_id = Column(Integer, ForeignKey("author.id"))
author = relationship("Author")
diff --git a/sqlalchemy_example/example_3/filter.py b/sqlalchemy_example/example_3/filter.py
index b75bc34593c0e15c198f95ec7df46b56fc6f638b..caefab910d2bd92db429e9ddb8edb705abf0163f 100644
--- a/sqlalchemy_example/example_3/filter.py
+++ b/sqlalchemy_example/example_3/filter.py
@@ -25,11 +25,7 @@ results = session.query(Person).filter(Person.address=='via Flavia')
# Print results
print('Persons in via Flavia are:')
for client in results:
- if client.type == 'person':
- print(client.id, client.name, client.surname)
- elif client.type == 'company':
- print(client.id, client.company_name, client.industry)
-
+ print(client.id, client.name, client.surname)
# Close session
session.close()