Simplified SQL Query Engine

An SQL engine which can execute a query written in a simplified form of Structured Query Language (SQL) against a simple database.

Simplified SQL

This SQL query engine handles a simplified version of SQL, supporting the following features:

• A SELECT clause, with any number of columns.
• A FROM clause, which identifies the primary table to select records from.
• Any number of optional JOIN clauses, treated as INNER JOINs. *An optional WHERE clause with only one condition.

Unsupported Features The engine does not support:

• Aliases (AS or [bracketed names]).
• CASTing.
• ORDER BY, GROUP BY, COUNT, or EXISTS.
• IN or LIKE, or any other operator other than simple equality, inequality, and greater than/less than.
• AND or OR; only a single WHERE condition is allowed.

SQL grammar

The SQL queries must adhere to the following EBNF grammar:

query         =  select, ws, from, [ ws, join ], [ ws, where ] ;
select        =  "SELECT ", column-id, [ { ", ", column-id } ] ;
from          =  "FROM ", table-name, [ { ws, join } ] ;
join          =  "JOIN ", table-name, " on ", value-test ;
where         =  "WHERE ", value-test ;
value-test    =  value, comparison, value;
column-id     =  table-name, ".", column-name ;
table-name    = ? a valid SQL table name ? ;
column-name   = ? a valid SQL column name ? ;
value         =  column-id | const
comparison    =  " = " | " > " | " < " | " <= " | " >= " | " <> " ;
const         =  ? a number ? | ? a SQL single-quoted string ? ;
ws            = " " | "\n" | ws, ws ;

Note that SQL is not case sensitive; SELECT and select are equivalent.

Valid Table and Column Names

A "valid SQL table/column name" is a name containing only letters, numbers, and the '_' character, with no spaces (/[a-zA-Z0-9_]+/).

Getting Started

Prerequisites

Ensure you have the following software installed before proceeding:

Rustc: Necessary to compile rust code.

Installation

1. Clone the Repository: Clone the project to your local machine using the following command:

git clone https://github.com/hiten52/Simple-SQL-Engine.git

2. Navigate to the Project Directory: Change into the project directory:

cd Simple-SQL-Engine

3. Type your query in "query" file

3. Run the Project: Run the project using Cargo:

cargo run