SQLite is an often overlooked flavor of SQL engines. Some have suggested it is the most prolific SQL engine in existence due to its highly flexible nature and ability to run on almost any platform with limited resources. Unlike other SQL engines like MySQL, PostgreSQL, MSSQL, or Oracle, SQLite runs without a server. SQLite does not rely on a data directory or a constantly running daemon: a database is encapsulated in a single file.
SQLite and iMessage
iMessage is one of the most popular messaging platforms today, largely because it is built into iOS and Mac devices. Since its release, it has evolved significantly. But, at its core, it is simply an instant messaging platform. iMessage uses SQLite in the background to store relational data about messages, conversations, and their participants.