Memento is relational; a library is equivalent to a table, and an entry is equivalent to a row. Libraries can be linked together in similar fashion to relational tables.
The set of a library's fields may be subdivided into pages. By default, fields fall into the page named "MAIN". Fields may be again subdivided by subheaders, which allow visual separation within a page.
When a value is stored for some field types, an external file is created or referenced, so the user's database consists of his or her libraries and its associated files.
In addition to fields, a library can contain aggregation functions to be displayed in entry lists.
A library can also be set up to autofill certain fields from Internet-based sources.
Libraries may be password-protected and encrypted to protect the privacy of their contents.
The set of a user's libraries may be subdivided into groups. By default, libraries fall into the group named My Libraries.
In the Mobile Edition, libraries are stored locally and may or may not be synchronized with the Memento Cloud along with their associated files. The Desktop Edition, however, works on libraries and files stored in the Memento Cloud.
Libraries may be imported from and exported to comma-delimited (CSV) files, which are often exported from or used to then import into other database products or spreadsheet file formats.
If the user is logged into a Google account, his or her libraries may be synchronized with Google Sheets files stored on the user's Google Drive. To do this, the library must already exist, so if the user wants to create a new library from a Google Sheet, the user must first create the library and its fields to match those of the Google Sheet and then set up the new library to synchronize with the Google Sheets file.