Usage Examples

database.writeTransaction {
    database.execute(
        sql = "DELETE FROM list WHERE id = ?",
        parameters = listOf(listId)
    )
    database.execute(
        sql = "DELETE FROM todos WHERE list_id = ?",
        parameters = listOf(listId)
    )
}

// You can watch any SQL query
fun watchCustomers(): Flow<List<User>> {
    // TODO: implement your UI based on the result set
    return database.watch("SELECT * FROM customers", mapper = { cursor ->
        User(
            id = cursor.getString("id"),
            name = cursor.getString("name"),
            email = cursor.getString("email")
        )
    })
}

suspend fun updateCustomer(id: String, name: String, email: String) {
    database.execute(
        "UPDATE customers SET name = ? WHERE email = ?",
        listOf(name, email)
    )
}

/**
 * This function is called whenever there is data to upload, whether the device is online or offline.
 * If this call throws an error, it is retried periodically.
 */
override suspend fun uploadData(database: PowerSyncDatabase) {

    val transaction = database.getNextCrudTransaction() ?: return;

    var lastEntry: CrudEntry? = null;
    try {

        for (entry in transaction.crud) {
            lastEntry = entry;

            val table = supabaseClient.from(entry.table)
            when (entry.op) {
                UpdateType.PUT -> {
                    val data = entry.opData?.toMutableMap() ?: mutableMapOf()
                    data["id"] = entry.id
                    table.upsert(data)
                }

                UpdateType.PATCH -> {
                    table.update(entry.opData!!) {
                        filter {
                            eq("id", entry.id)
                        }
                    }
                }

                UpdateType.DELETE -> {
                    table.delete {
                        filter {
                            eq("id", entry.id)
                        }
                    }
                }
            }
        }

        transaction.complete(null);

    } catch (e: Exception) {
        println("Data upload error - retrying last entry: ${lastEntry!!}, $e")
        throw e
    }
}

// Intialize the DB
val db = remember { PowerSyncDatabase(factory, schema) }
// Get the status as a flow
val status = db.currentStatus.asFlow().collectAsState(initial = null)
// Use the emitted values from the flow e.g. to check if connected
val isConnected = status.value?.connected

val db = remember { PowerSyncDatabase(factory, schema) }
val status = db.currentStatus.asFlow().collectAsState(initial = null)
val hasSynced by remember { derivedStateOf { status.value?.hasSynced } }

when {
    hasSynced == null || hasSynced == false -> {
        Box(
            modifier = Modifier.fillMaxSize().background(MaterialTheme.colors.background),
            contentAlignment = Alignment.Center
        ) {
                Text(
                    text = "Busy with initial sync...",
                    style = MaterialTheme.typography.h6
                )
            }
    }
    else -> {
    ... show rest of UI

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.material.LinearProgressIndicator
import androidx.compose.material.MaterialTheme
import androidx.compose.material.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.powersync.PowerSyncDatabase
import com.powersync.bucket.BucketPriority
import com.powersync.compose.composeState

/**
 * Shows a progress bar while a sync is active.
 *
 * The [priority] parameter can be set to, instead of showing progress until the end of the entire
 * sync, only show progress until data in the [BucketPriority] is synced.
 */
@Composable
fun SyncProgressBar(
    db: PowerSyncDatabase,
    priority: BucketPriority? = null,
) {
    val state by db.currentStatus.composeState()
    val progress = state.downloadProgress?.let {
        if (priority == null) {
            it
        } else {
            it.untilPriority(priority)
        }
    }

    if (progress == null) {
        return
    }

    Column(
        modifier = Modifier.fillMaxSize().background(MaterialTheme.colors.background),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center,
    ) {
        LinearProgressIndicator(
            modifier = Modifier.fillMaxWidth().padding(8.dp),
            progress = progress.fraction,
        )

        if (progress.downloadedOperations == progress.totalOperations) {
            Text("Applying server-side changes...")
        } else {
            Text("Downloaded ${progress.downloadedOperations} out of ${progress.totalOperations}.")
        }
    }
}