> All other RDBMS products also store their information inside files. No they don't. There are many RDBMS (and other DBMSs) that do not store their information

> All other RDBMS products also store their information inside files. No they don't. There are many RDBMS (and other DBMSs) that do not store their information inside files. > I can take a mdb file from SQL Server and copy it to another server and attach it there. Yes, SQL Server is an RDBMS. MDB files are files defined by a file format. This format defines something called a database. There are many libraries and other pieces of software than can read/write mdb files (https://jackcess.sourceforge.io/ https://jackcess.sourceforge.io/) SQLite files are files defined by a file format (https://www.sqlite.org/fileformat.html https://www.sqlite.org/fileformat.html). You can write code that reads and writes to a SQLite database file without using the library. So long as you follow the format specification, you will produce or be able to read from an aribtrary sqlite file that is produced by any code that implements the specification. The SQLite library is a reference implementation of the specification as well as some sample logic for reading/writing to the files and using SQL to define the interactions with the file. The SQLite library is not required for this, nor is SQL, nor is the logic for ACID compliance. SQLite is not an RDBMS and offers almost nothing that an RDBMS (or DBMS) might offer. If you wish to use SQLite files with an RDBMS you either have to build the RDBMS yourself, or find somebody else who's done so. The more you consider the SQLite a file format, the easier it becomes to work with and understand. The more you try to consider it an RDBMS the less it makes sense. Just because SQL is involved, doesn't mean it's an RDBMS.