SQLite is an in-process library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine.
SQLite is an embedded SQL database engine. Unlike most other SQL databases, SQLite does not have a separate server process. SQLite reads and writes directly to ordinary disk files. A complete SQL database with multiple tables, indices, triggers, and views, is contained in a single disk file. The database file format is cross-platform - you can freely copy a database between 32-bit and 64-bit systems or between big-endian and little-endian architectures. These features make SQLite a popular choice as an Application File Format.
Think of SQLite not as a replacement for Oracle but as a replacement for fopen()
Executive Summary