title	author	date	output
Relational Algebra Calculus	Deepak Yadav	17 October 2016	pdf_document

How to use Relation Algebra Calculator

1. select ($)

  syntax: $(table)(conditions)
  conditions support <, >, =, &, !, |, +, -, * operators only
  <= is not supported but same is possible using <, &, =
  similarly >= using >, &, =
  and != using !, =

2. project (#)

  syntax: #(table)(column1, column2, column3, ....)

3. union (U)

  syntax: U(first_table)(second_table)      

4. difference (D)

  syntax: D(first_table)(second_table)   

5. rename (R)

  syntax: R(old_table)(new_table_name[, new_column1_name, ...])      

6. cartesian product (C)

  syntax: C(first_table)(second_table)     

Calculator also support nested queries

project inside select

  $(#(table)(column1, column2, column3, ....))(conditions)

select inside project

  #($(table)(conditions))(column1, column2, column3, ....)

nesting can be complex

  C(R(U(#(table1)(column1, column2, column3, ....))($(table3)(conditions)))
   (new_table_name[, new_column1_name, ...]))
   (R(D($(table2)(conditions))(#(table4)(column1, column2, column3, ....)))
   (new_table_name[, new_column1_name, ...]))

Steps to run calculator

  1. open the terminal
  2. change the directory to Relational-Algebra-Calculator
  3. g++ -std=c++11 nested_query.cpp -o output.out
  4. ./output.out