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csv_query - A command line tool for performing SQL queries on CSV files

Simple usage:

make
./csv_query.native 'select * from employees.csv'

How to build

Run make to run the default target which builds the csv_query.native binary.

  1. mparser
  2. ounit (for testing)
  3. str

I still need to figure out how to extract the dependency specificaiton to a file and what command to use to automatically install them. I installed them manually using opam, eg. opam install mparser on my own machine.

How to test

Run make test to compile and run the test suite.

How does it work?

The query string is parsed using a simple monadic parser constructed using MParser. The code for the parser is located in QueryParser.ml. The parser returns a query data structure which can be found in Query.ml. The query can be executed by the execute_query function in QueryExecutor.ml to produce output based on the given SQL query.

Supported SQL features

  • SELECT *
  • SELECT a, b
  • csv files as table names, eg. FROM employees.csv

Future work

  • Add more SQL features (WHERE, JOIN, aggregate functions)
  • Add method for fetching dependencies easier
  • Add property based testing which would automatically generate a Query data value, print it as a string and then parse it back and check that the parsed query matches the original randomly generated one
  • Improve build process (I'm terrible at writing Makefiles)

Dev environment

I use VSCode with the OCaml plugin and Merlin. The code is built using ocamlbuild and ocamlfind