SQLite DB Implementation (Simplified Version)

Features

• Supports queries about database meta info (.dbinfo and .tables)
• Supports simple SELECT queries
• Supports specifying condition in WHERE clause
• Supports COUNT(*) aggregation query
• Supports using index to find rows efficiently

Sample Queries

SELECT COUNT(*) from table_1

SELECT col1, col2 FROM table_1

SELECT col1, col2 FROM table_1 WHERE col3="value"

Code Execution

Run the script called runner.sh.
It will run different queries on the sample.db (already present in the repository).

Using Other DB

There is another script called download_sample_databases.sh.
Executing this script will download two more database (superheroes.db and companies.db).

You can change the DB_PATH variable on the first line of runner.sh script and the queries accordingly to run on different database.

Using Index

In the companies.db there is an index on country column. So the following query will use that index and the execution time will improve.

 SELECT name, country FROM companies WHERE country = 'chad'