Kotlin Multiplatform (Beta)
Last updated
Last updated
Provides real-time streaming of database changes.
Offers direct access to the SQLite database, enabling the use of SQL on both client and server sides.
Operations are asynchronous by default, ensuring the user interface remains unblocked.
Supports concurrent database operations, allowing one write and multiple reads simultaneously.
Enables subscription to queries for receiving live updates.
Eliminates the need for client-side database migrations as these are managed automatically.
Supported targets: Android and iOS.
See the SDK's README for installation instructions.
Before implementing the PowerSync SDK in your project, make sure you have completed these steps:
The first step is defining the schema for the local SQLite database, which is provided to the PowerSyncDatabase
constructor via the schema
parameter. This schema represents a "view" of the downloaded data. No migrations are required — the schema is applied directly when the PowerSync database is constructed.
The types available are text
, integer
and real
. These should map directly to the values produced by the Sync Rules. If a value doesn't match, it is cast automatically.
Example:
Note: No need to declare a primary key id
column, as PowerSync will automatically create this.
Next, you need to instantiate the PowerSync database — this is the core managed database.
Its primary functions are to record all changes in the local database, whether online or offline. In addition, it automatically uploads changes to your app backend when connected.
Example:
a. Create platform specific DatabaseDriverFactory
to be used by the PowerSyncBuilder
to create the SQLite database driver.
b. Build a PowerSyncDatabase
instance using the PowerSyncBuilder
and the DatabaseDriverFactory
. The schema you created in a previous step is provided as a parameter:
c. Connect the PowerSyncDatabase
to the backend connector:
Special case: Compose Multiplatform
The artifact com.powersync:powersync-compose
provides a simpler API:
Create a connector to integrate with your backend. The PowerSync backend connector provides the connection between your application backend and the PowerSync managed database.
It is used to:
Retrieve an auth token to connect to the PowerSync instance.
Apply local changes on your backend application server (and from there, to Postgres)
Accordingly, the connector must implement two methods:
PowerSyncBackendConnector.fetchCredentials
- This is called every couple of minutes and is used to obtain credentials for your app backend API.
-> See Authentication Setup for instructions on how the credentials should be generated.
PowerSyncBackendConnector.uploadData
- Use this to upload client-side changes to your app backend.
-> See Writing Client Changes for considerations on the app backend implementation.
Example:
Note: If you are using Supabase, you can use SupabaseConnector.kt as a starting point.
Once the PowerSync instance is configured you can start using the SQLite DB functions.
The most commonly used CRUD functions to interact with your SQLite data are:
PowerSyncDatabase.get
- get (SELECT) a single row from a table.
PowerSyncDatabase.getAll
- get (SELECT) a set of rows from a table.
PowerSyncDatabase.watch
- execute a read query every time source tables are modified.
PowerSyncDatabase.execute
- execute a write (INSERT/UPDATE/DELETE) query.
The get
method executes a read-only (SELECT) query and returns a single result. It throws an exception if no result is found. Use getOptional
to return a single optional result (returns null
if no result is found).
The getAll
method executes a read-only (SELECT) query and returns a set of rows.
The watch
method executes a read query whenever a change to a dependent table is made.
The execute
method executes a write query (INSERT, UPDATE, DELETE) and returns the results (if any).
See Usage Examples for further examples of the SDK.
ORM support is not yet available, we are still investigating options. Please let us know what your needs around ORMs are.
To access the source code for this SDK, refer to powersync-kotlin
repo on GitHub.
See Troubleshooting for pointers to debug common issues.
API Reference (Coming soon)
A full API Reference for this SDK is not yet available. This is planned for the stable release.