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