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Note: SystemId and Sid are synonyms. For the purpose of this document will use Sid when referring to System ID.

Model developers can create define attribute of type SystemId or Sid.

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When the Model Instance is created, using Create TQL Query, System ID value is automatically generated by TQLEngine.

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<Find Status="Success">
  <Result>
    <PhidgetServoModel>
      <PhidServoId>KNI5JYVPAAAAUAABA4ONNHF2</PhidServoId>
      <PhidgetDeviceType>PhidgetAdvancedServo</PhidgetDeviceType>
      <ServoAngle>110</ServoAngle>
      <DeviceInterfaceIndex>0</DeviceInterfaceIndex>
      <ServoProtocolURL>phid://</ServoProtocolURL>
    </PhidgetServoModel>
  </Result>
</Find>

Note that the PhidServoId value is automatically generated even though it is NOT specified at the time of Create Query

<PhidServoId>KNI5JYVPAAAAUAABA4ONNHF2</PhidServoId>

About System ID:

• Are Unique Have unique values per Installation of TQLEngine: System ID Values are guaranteed to be Unique for a given Installation of TQLEngine.
• Can Value can neither be created given or modified by user: If an attribute is defined of type Sid or SystemId, their values can neither be specified or updated by the user.
• New Values values are generated each time for same model: Each time an instance is deleted and created again new value System ID value.

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