If you want to play around with a lightweight SQL RDBMS, SQLite (Ubuntu package) is the standard choice. You have multiple options to use SQLite:

Command-line

You can use the SQLite program directly from the command line by running

sqlite3 /some/database/file.sqlite

Type commands and press Enter (remember the trailing semicolon).

GUI

Alternatively, you can install sqliteman, which provides a nice GUI browser for SQLite databases; you can also enter SQL code and execute it (displaying the results in the GUI):

Install via terminal:

sudo apt-get install sqliteman

Or:

Caveat

Be aware that SQLite takes some unusual design decisions for an RDBMS:

• No client-server architecture


• Dynamically typed; SQLite does not enforce many constraints that other RDBMSs insist on. If you want to simulate MySQL-like typing, you have to explicitly add CHECK constraints.