DatabaseUpdate

Description

The DatabaseUpdate object is used to update objects in a database table. The API is identical to DatabaseQuery except for the execute() method.

This object was introduced in InCore 2.5.

› Inherits:DatabaseQuery

Overview

Properties

DatabaseQuery.error DatabaseQuery.errorString DatabaseQuery.filters DatabaseQuery.limitLength DatabaseQuery.limitPos DatabaseQuery.objects

DatabaseQuery.orderBy DatabaseQuery.orderByNames DatabaseQuery.results DatabaseQuery.table Object.objectId Object.parent

Methods

execute() DatabaseQuery.execute() DatabaseQuery.pollResults() Object.deserializeProperties() Object.fromJson() Object.serializeProperties() Object.toJson()

Signals

DatabaseQuery.errorOccurred() DatabaseQuery.filtersDataChanged() DatabaseQuery.objectsDataChanged() DatabaseQuery.orderByDataChanged() Object.completed()

Enumerations

DatabaseQuery.Error

Properties

Methods

execute()

This method updates the columns specified by DatabaseQuery.objects and rows filtered through DatabaseQuery.filters. If at least one row has been updated and no error occurred, true is returned, otherwise false. The number of updated rows can be retrieved using the DatabaseQuery.results property.

› Returns:Boolean

Example

import InCore.Foundation 2.5
import InCore.Database 2.5

Application {

    LocalDatabase {
        id: exampleDatabase

        DatabaseTable {
            id: exampleTable

            // submit a new data row every 10s
            submitInterval: 10000
            submitMode: DatabaseTable.SubmitPeriodically
            onSubmitted: lastIdQuery.execute()

            DataObject {
                id: exampleTableId
                objectId: "id"
                dataType: DataObject.SignedInteger
                DatabaseFieldOptions.primaryKey: true
                DatabaseFieldOptions.autoIncrement: true
            }

            Measurement {
                id: sensor1
                data: 1
                onDataChanged: updateSensor1.execute()
            }

            Measurement {
                id: sensor2
                data: 123
            }

            queries: [
                // always update last row with latest value of sensor1
                DatabaseUpdate {
                    id: updateSensor1
                    objects: [sensor1]
                    DatabaseQueryFilter {
                        DatabaseQueryWhere {
                            key: exampleTableId
                            operation: DatabaseQueryWhere.Equals
                            value: lastIdQuery.results[0] ? lastIdQuery.results[0].id : -1
                        }
                    }
                },
                DatabaseQuery {
                    id: lastIdQuery
                    objects: [exampleTableId]
                    orderByNames: ["-id"]
                    limitPos: 0
                    limitLength: 1
                }
            ]
        }
    }

    Timer {
        onTriggered: sensor1.data = Math.random() * 100
    }
}