We continue our series on “modern persistence” with an important topic: “callbacks.” Callbacks are little hooks into the lifecycle of your data model so that you can be notified or take action when something changes. We will first explore the “Active Record” pattern of callbacks, popularized by Ruby on Rails, and then see how we can improve upon them.

How does our SQL-based solution for persistence compare with modern SwiftData? We put things to the test by rebuilding our complex @FetchAll query using @Model and the @Query macro!

We finish a sneak peek of our upcoming Structured Queries library by showing how queries built with the library can be reused and composed together, and how we can replace all of the raw queries in our application with simpler, safer query builders.

We start to leverage SQLite’s built-in full-text search capabilities to power our feature. We learn about virtual tables, create one that stores the searchable data, populate it with the help of database triggers, and show just how powerful and succinct search can be.

We now have a very basic search feature in place, but it can be improved. We will add some bells and whistles and other performance improvements, including debouncing database queries, adding a count query to display the number of completed reminders, and grouping the queries into a single transaction.

Search is a natural feature to add to an app once your user has stored a whole bunch of data. We will tackle the problem from the perspective of modern persistence using SQLite as your data store by adding a simple search feature to our rewrite of Apple’s Reminders app.