Whats wrong with SQLite?
Note1: "SQLite is an open-source, embedded, relational database management system. It is a lightweight database, with zero configuration, no requirements of a server or installation. Despite its simplicity, it is equipped with common functions of database management systems."
Note2: "The fact that the entire database is portable as a single file made migrating content from one system to another easy and fool-proof."
//Edit: Various limitations should be considered.
SQLite Frequently Asked Questions[
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Perhaps you will also look at:
https://www.g2.com/products/sqlite/competitors/alternatives[
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