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iOS-SwiftUI-Code/GRDB.swift-6.29.3/GRDB/Documentation.docc/DatabaseObservation.md

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+# Database Observation
+
+Observe database changes and transactions.
+
+## Overview
+
+**SQLite notifies its host application of changes performed to the database, as well of transaction commits and rollbacks.**
+
+GRDB puts this SQLite feature to some good use, and lets you observe the database in various ways:
+
+- ``ValueObservation``: Get notified when database values change.
+- ``DatabaseRegionObservation``: Get notified when a transaction impacts a database region.
+- ``Database/afterNextTransaction(onCommit:onRollback:)``: Handle transactions commits or rollbacks, one by one.
+- ``TransactionObserver``: The low-level protocol that supports all database observation features.
+
+## Topics
+
+### Observing Database Values
+
+- ``ValueObservation``
+- ``SharedValueObservation``
+- ``AsyncValueObservation``
+- ``Database/registerAccess(to:)``
+
+### Observing Database Transactions
+
+- ``DatabaseRegionObservation``
+- ``Database/afterNextTransaction(onCommit:onRollback:)``
+
+### Low-Level Transaction Observers
+
+- ``TransactionObserver``
+- ``Database/add(transactionObserver:extent:)``
+- ``Database/remove(transactionObserver:)``
+- ``DatabaseWriter/add(transactionObserver:extent:)``
+- ``DatabaseWriter/remove(transactionObserver:)``
+- ``Database/TransactionObservationExtent``
+
+### Database Regions
+
+- ``DatabaseRegion``
+- ``DatabaseRegionConvertible``