SQLite supports several datatypes: NULL for empty, INTEGER and REAL for signed integers and floating point values respectively, TEXT for text strings, and BLOB for binary files.

You convert old Sticky Notes StickyNotes.snt data file to the new Sticky Notes plum.sqlite data file so that you can use the Windows 7 legacy Sticky Notes on Windows 11/10.

XnView uses an SQLite database for storing this info and accessing it; Windows uses a flat file for the image metadata and another for the actual image thumbnails.