There are three types of Models that can be defined at the time of creating models for your IoT applications. The three models are:
- DataModel
- ThingModel
- AppModel
See Models for details.
Model lifecycle consists of three steps
- Definition - Models are defined either using TQLStudio Model Editor or any IDE of your choice. Modeling Language (Thing Definition Language) is essential to define models.
- Deploy - As part of a deployable unit within TQLEngine's package file. Models definitions are made part of SffTqlFacet Facet type.
- Query - Querying of model consists of CRUD as well as Subscription (and notification).
Model Instances
Once models are defined and deployed their schematic layout is persisted in Storage (TQL Cache) defined at the time of the deployment. Note that even though models are persisted in SQL type of storage that data is highly unstructured and stored in proprietary format.
Before Models can be queried using Find - Models must be initialized or populated with data. The result of model creation is called Model Instances.
For example: Here is the definition of a ThingModel - PhidgetSensorModel that combines PhidgetSensorFacet.
Definition
<ThingFacet Name="PhidgetSensorFacet"> <Integer Name="SensorValue" Update="auto" KnownBy="PhidgetSensorAction"/> <String Name="SensorURL" Default="phid://"/> <String Name="SensorInterfaceIndex"/> <String Name="SensorType"/> <String Name="SensorInterfaceType"/> <String Name="SensorValueFormat"/> <String Name="Simulated"/> </ThingFacet> <ThingModel Name="PhidgetSensorModel" Combines="PhidgetSensorFacet"> <Sid Name="phidId"/> </ThingModel>
Deploy and Create:
The instances of PhidgetSensorModel is created using Create TQL Query.
<Query> <Create> <PhidgetSensors> <SensorURL>phid://</SensorURL> <SensorType>Rotation</SensorType> <SensorInterfaceType>PhidgetInterfaceKit</SensorInterfaceType> <SensorValueFormat>Raw</SensorValueFormat> <SensorInterfaceIndex>0</SensorInterfaceIndex> <SensorValue value="$Null()" version="1"/> <Simulated>true</Simulated> </PhidgetSensors> </Create> </Query>
The Result of Model Instance Creation is:
Note that there is Status returned for every attribute that gets created.
<Create Status="Success"> <PhidgetSensors> <phidId>KNUBPHLOAAAAUAABA6EJCI75</phidId> <SensorValue Status="Success+Created:1:1457740291438;" Value="" Version="1"/> <SensorURL Status="Success+Created:1:1457740291442;" Value="phid://" Version="1"/> <SensorInterfaceIndex Status="Success+Created:1:1457740291443;" Value="0" Version="1"/> <SensorType Status="Success+Created:1:1457740291444;" Value="Rotation" Version="1"/> <SensorInterfaceType Status="Success+Created:1:1457740291444;" Value="PhidgetInterfaceKit" Version="1"/> <SensorValueFormat Status="Success+Created:1:1457740291445;" Value="Raw" Version="1"/> <Simulated Status="Success+Created:1:1457740291445;" Value="true" Version="1"/> </PhidgetSensors> </Create>
Find Model Instances
After Model Instances are created, you can Read them using Find Query with constraints.
<Query> <Find format="all"> <PhidgetSensors> <SensorURL ne =""/> </PhidgetSensors> </Find> </Query>
Find Query Result
<Find Status="Success" Format="all"> <Result> <PhidgetSensors QName="SimpleModel.MyModels.PhidgetSensors"> <phidId>KNUBPHLOAAAAUAABA6EJCI75</phidId> <SensorValue Value="" Known="60" Version="1" Timestamp="1457740291438" DateTime="2016-03-11 15:51:31.438" QName="SimpleModel.MyModels.PhidgetSensors.SensorValue" FName="SensorValue"/> <SensorURL Value="phid://" Known="phid://" Version="1" Timestamp="1457740291442" DateTime="2016-03-11 15:51:31.442" QName="SimpleModel.MyModels.PhidgetSensors.SensorURL" FName="SensorURL"/> <SensorInterfaceType Value="PhidgetInterfaceKit" Known="PhidgetInterfaceKit" Version="1" Timestamp="1457740291444" DateTime="2016-03-11 15:51:31.444" QName="SimpleModel.MyModels.PhidgetSensors.SensorInterfaceType" FName="SensorInterfaceType"/> <Simulated Value="true" Known="true" Version="1" Timestamp="1457740291445" DateTime="2016-03-11 15:51:31.445" QName="SimpleModel.MyModels.PhidgetSensors.Simulated" FName="Simulated"/> <SensorInterfaceIndex Value="0" Known="0" Version="1" Timestamp="1457740291443" DateTime="2016-03-11 15:51:31.443" QName="SimpleModel.MyModels.PhidgetSensors.SensorInterfaceIndex" FName="SensorInterfaceIndex"/> <SensorType Value="Rotation" Known="Rotation" Version="1" Timestamp="1457740291444" DateTime="2016-03-11 15:51:31.444" QName="SimpleModel.MyModels.PhidgetSensors.SensorType" FName="SensorType"/> <SensorValueFormat Value="Raw" Known="Raw" Version="1" Timestamp="1457740291445" DateTime="2016-03-11 15:51:31.445" QName="SimpleModel.MyModels.PhidgetSensors.SensorValueFormat" FName="SensorValueFormat"/> </PhidgetSensors> </Result> </Find>
Status: This is a transient attribute returned as part of the result of TQL Create/Save, Update and Delete operations. It is not persisted.