Add Bookstore example

.gitignore

@@ -48,3 +48,5 @@ bazel-*
 
 # Distribution
 dist/
+.typedb-studio/
+

README.md

@@ -68,3 +68,9 @@ constraints, all at query (run) time.
 [TypeDB CTI](https://github.com/typedb-osi/typedb-cti) is an open source threat intelligence platform for organisations
 to store and manage their cyber threat intelligence (CTI) knowledge. It enables threat intel professionals to bring
 together their disparate CTI information into one database and find new insights about cyber threats.
+
+## [Commerce: Bookstore](commerce/bookstore)
+
+The bookstore example uses python to showcases migration of data into TypeDB and executing queries on this data. 
+
+Read the [README](commerce/bookstore/README.md) file for instructions. Check [the schema](commerce/bookstore/schema.tql) or the initial [dataset](commerce/bookstore/python/data) for additional information. All logic accessible in the script files.

commerce/bookstore/README.md

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+# Bookstore example
+
+[![forthebadge](https://forthebadge.com/images/badges/made-with-python.svg)](http://forthebadge.com) [![forthebadge](images/made-with-typedb.svg)](https://forthebadge.com)
+
+This is a simple example of using TypeDB.
+
+## Introduction
+
+We have imaginary online Bookstore and our script/application implements some very basic functions:
+
+- Search for a Book
+- Search for a User
+- Search for an Order
+- Search for books by genre
+
+This application consists of two python scripts. It has not much in terms of usability as it is merely a demonstration of TypeDB queries. 
+
+You can clearly see the implementation of mentioned functions in the source codes.
+
+## Prerequisites
+
+* [TypeDB](https://docs.vaticle.com/docs/running-typedb/install-and-run) v2.14.1+
+* Python v.3.9+
+* `typedb.client` — [python client](https://docs.vaticle.com/docs/client-api/python) for TypeDB
+* This repository
+
+## Quickstart
+
+1. Checkout this repository: `git clone https://github.com/vaticle/typedb-examples && cd typedb-examples`
+2. Start the [TypeDB Server](http://docs.vaticle.com/docs/running-typedb/install-and-run#start-the-typedb-server). Check that it's listening to address: `0.0.0.0:1729`.
+3. Launch `typedb-examples/commerce/bookstore/python/load_data.py` python script. It will load the bookstore schema and data into the DB.
+4. Launch `typedb-examples/commerce/bookstore/python/requests.py` python script and follow the instructions to explore example functions and data.
+5. Use this simple example to learn the basics of using TypeDB! Explore source codes of the both python scripts and TypeDB Studio to explore DB schema and content.
+
+## How it works
+
+### Files
+
+This example located in the `typedb/commerce/bookstore/` directory and consists of the following main files:
+- Python scripts
+  - `python/load_data.py` — used to load the bookstore DB schema and data
+  - `python/requests.py` — provides simple command line interface to execute requests on TypeDB database
+- `schema.tql` — DB schema
+- `README.md` — documentation for the bookstore example. You are reading it right now
+- Bookstore dataset `python/data/`:
+  - `books.csv`
+  - `users.csv`
+  - `ratings.csv`
+  - `order.csv`
+  - `genres.csv`
+- `request-examples/` — directory with examples of requests for the database. Files of `.tql` format can be used in Type DB Studio directly or to create a request for other TypeDB clients
+
+### Schema
+
+The schema stored in the `schema.tql` file and loaded by the `load_data.py` script.
+
+![bookstore_schema](images/bookstore_schema.png)
+
+#### Attributes
+
+The bookstore schema has the following attributes:
+
+- name (string)
+- description (string )
+- id (string) 
+- ISBN (string) 
+- Book_Author (string) 
+- Publisher (string) 
+- foreign-user-id (string) 
+- status (string) 
+- delivery_address (string) 
+- payment_details (string) 
+- username (string) 
+- password (string) 
+- foreign-id (string) 
+- genre (string) 
+
+- date (datetime)
+
+- price (long) 
+- stock (long) 
+- rating (long) 
+- age (long)
+
+
+#### Entities
+
+The bookstore schema has the following entities:
+
+- Product 
+  - Book
+- Person
+  - User
+- Order
+
+#### Relations
+
+The bookstore schema has the following relations:
+
+- reviewing
+- taging 
+- ordering 
+- tag-hierarchy
+
+#### Rules
+
+The bookstore schema has two rules to demonstrate rules usability.
+
+The first one works for genre tags, serves no real purpose but follows the following basic logic — a child (sub-tag) of my child is my child. The first rule text:
+
+```
+rule super-tag-hierarchy:
+    when {
+        $b isa genre;
+        $p isa genre;
+        $bb isa genre;
+        (sup-tag: $p, sub-tag: $b) isa tag-hierarchy;
+        (sup-tag: $b, sub-tag: $bb) isa tag-hierarchy;
+    } then {
+        (sup-tag: $p, sub-tag: $bb) isa tag-hierarchy;
+    };
+```
+
+The second one works also for genre tags, used to improve tag searching experience. By assigning tag to a book you are also assigning all sup-tags to the same book. So the book can be found not only by exact tag you have assigned to it, but also by all of its parent tags.
+
+```
+rule super-tag:
+    when {
+        $book isa Book;
+        $tag (tag:$g, book: $b) isa taging;
+        $g isa genre;
+        $sup isa genre;
+        (sup-tag: $sup, sub-tag: $g) isa tag-hierarchy;
+    } then {
+        (tag:$sup, book: $b) isa taging;
+    };
+```