Relational-Algebra-Query-Processor

3005 bonus assignment
CLI program for processing relational algebra queries.

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Features

This program supports the following relational algebra operations:

• Selection (σ): Filter rows based on a condition.
• Projection (π): Select specific columns from a relation.
• Join (⋈): Combine rows from two relations based on a related column.
• Union (⋃): Combine all rows from two relations, removing duplicates.
• Intersection (∩): Return rows present in both relations.
• Difference (−): Return rows from the first relation not present in the second.

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Usage and Commands

The CLI accepts commands to process relational algebra queries on your input data. Key features and commands include:

• Query:
  Enter a relational algebra expression to be processed.
  Example:

  Query: project SID, Name (select Age = 50 (Students))
  

• select
  Filter rows based on a condition.
  Example:

  Query: select Name = 'Siddig' (Students_3)
  

• project
  Select specific columns from a relation.
  Example:

  Query: project Name (select GPA > 10.5 (Students_3))
  

• join
  Combine rows from two relations based on a common column.
  Example:

  Query: Students_3 join Students2 on GPA > 10.8
  

• union
  Combine all rows from two relations, removing duplicates.
  Example:

  Query: Students_3 union Students2
  

• intersection
  Return rows present in both relations.
  Example:

  Query: Students_3 intersection Students2
  

• difference
  Return rows from the first relation not present in the second.
  Example:

  Query: Students_3 difference Students2
  

• Input/Output:

  • Input file: Define your relations and queries.
  • Output file: Results are written here after processing.

Refer to the examples above to construct your queries in the CLI.

Running the Program

1. Fill the input file
   Prepare your input file with the required relations and queries.

2. Run the program

   python app.py

3. Open the output file
   View the results in the output file.

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Notes

• Ensure your input file is formatted correctly.