Create a sqlite database file by using sqlite3 from the command line and simply typing .save empty.db
then .exit
$ sqlite3
SQLite version 3.8.10.2 2015-05-20 18:17:19
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database.
sqlite> .save empty.db
sqlite> .exit
KNIME lets you import and visualize the database as well as run pure SQL and assisted queries.
Here you can download an example workflow and empty database
You can also use SQLite and follow the tutorial listed here