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Once models are defined and deployed the meta structure of the model definition is stored in memory. (If TQLEngine A-Stack shuts down and restart, the model definitions will be reloaded. The but model instance data will persist.)
Before Find queries can find anything from the models, they must be instantiated, or populated with data. The result of model instantiation is called Model Instances. Multiple model instances can be created from the same model (definition). Model instance data is persisted in the storage (TQLCache), as defined at the time of the deployment.
| Note |
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Even though TQLEngine A-Stack uses SQL type of database technology to persist model instances, they are stored in a schema-less way, not in a relational format. This preserves the the performance at scale. |
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Definition
| Code Block |
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| language | ruby |
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| theme | xmlEmacs |
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| title | PhidgetSensor Thing Model |
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| linenumbers | true |
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<ThingFacet#
ThingFacet(Name=: "PhidgetSensorFacet">):
<Integer Name=Integer(Name: "SensorValue", Update=: "auto", KnownBy=: "PhidgetSensorAction"/>)
<String Name=String(Name: "SensorURL", Default=: "phid://"/>)
<String Name=String(Name: "SensorInterfaceIndex"/>)
<String Name=String(Name: "SensorType"/>)
<String Name=String(Name: "SensorInterfaceType"/>)
<String Name=String(Name: "SensorValueFormat"/>)
<String Name=String(Name: "Simulated"/>
</ThingFacet>
<ThingModel Name=)
ThingModel(Name: "PhidgetSensorModel", Combines=: "PhidgetSensorFacet">):
<Sid Name=Sid(Name: "phidId"/>
</ThingModel>) |
Create model instances
The model instances of PhidgetSensorModel is created using a Create TQL Query.
| Code Block |
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| language | ruby |
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| theme | xmlEmacs |
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| title | Create PhidgetSensor ThingModel Instance |
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| linenumbers | true |
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<Query>#
Query:
Create:
<Create> PhidgetSensors:
<PhidgetSensors> SensorURL: <SensorURL>phidphid://</SensorURL>
SensorType: Rotation
<SensorType>Rotation</SensorType> SensorInterfaceType: PhidgetInterfaceKit
<SensorInterfaceType>PhidgetInterfaceKit</SensorInterfaceType> <SensorValueFormat>Raw</SensorValueFormat>SensorValueFormat: Raw
SensorInterfaceIndex: <SensorInterfaceIndex>0</SensorInterfaceIndex>0
<SensorValue SensorValue(value=: "$Null()", version=: "1"/>);
<Simulated>true</Simulated>
</PhidgetSensors>
</Create>
</Query>Simulated: true |
The result of model instance creation is below.
Note that there is Status returned for every attribute that gets created.
| Code Block |
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| language | xmlruby |
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| theme | Emacs |
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| title | Create PhidgetSensor ThingModel Instance Result |
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| linenumbers | true |
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<Create#
Create(Status=: "Success">):
<PhidgetSensors>PhidgetSensors:
<phidId>KNUBPHLOAAAAUAABA6EJCI75</phidId>phidId: KNUBPHLOAAAAUAABA6EJCI75
<SensorValue SensorValue(Status=: "Success+Created:1:1457740291438;", Value=: "", Version=: "1"/>)
<SensorURL Status=SensorURL(Status: "Success+Created:1:1457740291442;", Value=: "phid://", Version=: "1"/>)
<SensorInterfaceIndex Status=SensorInterfaceIndex(Status: "Success+Created:1:1457740291443;", Value=: "0", Version=: "1"/>)
<SensorType Status=SensorType(Status: "Success+Created:1:1457740291444;", Value=: "Rotation", Version=: "1"/>)
<SensorInterfaceType Status=SensorInterfaceType(Status: "Success+Created:1:1457740291444;", Value=: "PhidgetInterfaceKit", Version=: "1"/>)
<SensorValueFormat Status=SensorValueFormat(Status: "Success+Created:1:1457740291445;", Value=: "Raw", Version=: "1"/>)
<Simulated Status=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.
| Code Block |
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| language | rubyxml |
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| theme | Emacs |
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| title | Find PhidgetSensor ThingModel Instance |
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| linenumbers | true |
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<Query>#
Query:
<FindFind format=: "all">):
<PhidgetSensors>PhidgetSensors:
<SensorURL SensorURL(ne : =""/>
</PhidgetSensors>
</Find>
</Query>) |
Find Query Result
| Code Block |
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| language | ruby |
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| theme | xmlEmacs |
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| title | Find PhidgetSensor ThingModel Instance |
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| linenumbers | true |
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<Find Status=#Find(Status: "Success", Format=: "all">):
Result:
<Result>
<PhidgetSensors QName= PhidgetSensors(QName: "SimpleModel.MyModels.PhidgetSensors">
<phidId>KNUBPHLOAAAAUAABA6EJCI75</phidId>
<SensorValue Value="" Known="60" Version="1" Timestamp="1457740291438" DateTime=):
phidId: KNUBPHLOAAAAUAABA6EJCI75
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=)
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=)
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=)
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=)
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=)
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=)
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>) |
| Note |
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The following system generated tags are for each attribute: | Include Page |
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| System generated tags for attributes |
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| System generated tags for attributes |
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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.