The Card defines the basic element of Protogrid. Everything is stored in some kind of Card. For instance, properties of an App are edited via the card “Application Settings”. This is also the first card of a new app.

Mostly, Cards define your data based on some kind of Proto, which you can open by using the Option “This Card → Open Proto” in the bottom right corner. Cards can also be accessed through the JSON-API.

Comparison with relational databases

While in relational databases, a single data entry is given by a row of a table, a card represents the data entry in Protogrid. If you have a table “books” in which each entry has an attribute “ID”, “Name”, “Author”, each of these attributes corresponds to a field on a card in Protogrid.

Meta-information about a card

You can display the properties of a card such as a card's ID, its creator and creation date using the option “This Card → Show Properties”. Using the option “This Card → Show Mutation History” you can see all changes made to that card, including information about deletion and restoration of a card. Furthermore, whenever you add an attachment to the card, this is also logged in the mutation history.