DatabaseQueryFilter

Description

The DatabaseQueryFilter object represents a query filter used in DatabaseQuery objects. Each filter consists of a set of DatabaseQueryWhere objects which are combined using logical OR. This means that one of the defined WHERE conditions have to match to make the whole filter match for a particular row.

› Inherits:Object

Overview

Properties

where Object.objectId Object.parent

Methods

Object.deserializeProperties() Object.fromJson() Object.serializeProperties() Object.toJson()

Signals

whereDataChanged() Object.completed()

Properties

where

This property holds one or multiple DatabaseQueryWhere instances or references to them used to create an SQL query for this filter.

› Type:List<DatabaseQueryWhere> › Signal:whereChanged() › Attributes:Readonly

Signals

whereDataChanged(SignedInteger index)

This signal is emitted whenever the List.dataChanged() signal is emitted, i.e. the item at index in the where list itself emitted the dataChanged() signal.

Example

import InCore.Foundation 2.5
import InCore.Database 2.5

Application {

    LocalDatabase {
        id: exampleDatabase

        DatabaseTable {
            id: exampleTable

            DateTime { id: date }
            Measurement { id: temperature1 }
            Measurement { id: temperature2 }

            queries: [
                DatabaseQuery {
                    id: exampleQuery
                    DatabaseQueryFilter {
                        DatabaseQueryWhere { key: temperature1; operation: DatabaseQueryWhere.GreaterThan; value: 20 }
                        DatabaseQueryWhere { key: temperature2; operation: DatabaseQueryWhere.LessThan; value: 30 }
                    }

                    onResultsChanged: console.log(toJson(results))
                }
            ]
        }
    }

    Timer {
        onTriggered: {
            temperature1.data = 25 - Math.random() * 20
            temperature2.data = 25 + Math.random() * 20
            exampleTable.submit()
            exampleQuery.execute()
        }
    }

    onCompleted: exampleTable.drop()
}