THE PROJECT HAS MOVED =====================

The new repository is https://codeberg.org/ltworf/relational

Relational ==========

Relational an educational tool to provide a workspace for experimenting with relational algebra, an offshoot of first-order logic.

I test it on GNU/Linux and Windows. It probably works on other systems too.

It provides: * A GUI that can be used for executing relational queries * A standalone Python module that can be used for executing relational queries, parsing relational expressions and optimizing them * A command line interface

Official website ================

More documentation can be found here https://ltworf.github.io/relational/

Install =======

• Windows: https://ltworf.github.io/relational/download.html?exe
• Debian based: apt-get install relational
• Everyone else: Download the sources https://ltworf.github.io/relational/download.html?tar.gz

Run from sources ================

For the dependencies, check debian/control for the build dependencies.

You will need to run

make

To launch the application, run

./relational.py

Syntax ======

These are some valid queries (using the provided example dataset)

# Join people and skills
people ⋈ skills
Select people within a certain age range
σ age > 25 and age < 50 (people)
Selection with complicated expression requires an extra set of () around the expression
σ (name.upper().startswith('J') and age > 21) (people)
Cartesian product of people with itself, including only name and id
ρ id➡i, name➡n (people) * π name, id (people)

For the selection, python expressions are used.

The syntax is explained here: https://ltworf.github.io/relational/allowed_expressions.html