Copy of Model instance data

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.

In TQL Model development is a three step process -

Definition
Deploy (compilation)
Queries (instantiation, update, delete, subscription)

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

PhidgetSensor Thing Model

<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.

Create PhidgetSensor ThingModel Instance

<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 PhidgetSensor ThingModel Instance Result

<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.

Find PhidgetSensor ThingModel Instance

<Query>
  <Find format="all">
    <PhidgetSensors>
      <SensorURL ne =""/>
    </PhidgetSensors>
  </Find>
</Query>

Find Query Result

Find PhidgetSensor ThingModel Instance

<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>

The following system generated tags are for each attribute:

A-Stack automatically generates tags as part of every attribute that makes up the model definition. System tags can be read (using FIND) with

Format="all" modifier with the <Find> Query.

System Tag Name	Description	Persisted?	Query Constraint?
Value	The value of the attribute is stored in "Value". This is often specified by the user at the time of create query (instantiation)	Yes	Yes
Known	Applicable to ThingModel/AppModel - this is the value that is only set by the output of Actions. Known CANNOT be set using CRUD operations (Create / Update) via TQL Queries. The system also maintains a "Known" for DataModel attributes, for consistency purposes, but it will always be the same as Value.	Yes	No
Version	The version number of the attribute. This number is automatically incremented each time the value changes.	Yes	No. You can request the value using Format on <Find>
Timestamp	Unix epoch time at the time (in millisecond) of the attribute creation. For example: Timestamp value 1457663102004 is same as Fri, 11 Mar 2016 02:25:02 GMT	Yes	No
Datetime	Formatted data time value of the attribute creation. For example: 2016-03-10 18:25:02.004	Yes	No
QName	Fully qualified name of the attribute. <NamSpace>.<Domain>.<ModelName>.<AttributeName>. For example SimpleModel.MyModels.VendorInfo.vendorName given that VendorInfo is defined within Namespace - SimpleModel, with Domain as MyModels and DataModel Name as VendorInfo	Yes	No
FName	Given name of the attribute name.	Yes	No

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Status: This is a transient attribute returned as part of the result of TQL Create/Save, Update and Delete operations. It is not persisted.