Row level security
Row level security is a rule inside the database that decides which rows each person is allowed to see or change.
In a simple example
Each customer can read only their own bookings, even if they try to ask for everyone's.
Why it matters to you
Without it, anyone who finds your app's public address might read all your customers' data.
Do not confuse with
It is a lock on the data itself. A hidden button in the app is not a lock.