We famously call such attributes as "CherryPicked Attributes". They are "Cherry Picked" from the attributes of some other defined models.
CherryPicked attributes are defined as type of Attribute. The value is defined as the name of an attribute from another model. For example, <Attribute name="SensorVendorSysId" value="VendorInfo.VendorSysId"/>.
In this example the DataModel SensorVendorInfo contains SensorVendorSysId, SensorVendorName defined and available from DataMdoel VendorInfo.
# DataModel(Name: "VendorInfo"): Sid(Name: "VendorSysId") String(Name: "VendorName") String(Name: "VendorTitle") PostalAddress(Name: "VendorAddress") String(Name: "DeviceTypes", Cardinality: "0..m") Unique(Name: "UniqueVendorName", Value: "VendorName") DataModel(Name: "SensorVendorInfo"): Attribute(Name: "SensorVendorSysId", value: "VendorInfo.VendorSysId") Attribute(Name: "SensorVendorName", value: "VendorInfo.VendorName")
Once VendorInfo Data is created using Create TQL Query. The SensorVendorInfo will automatically have the Data as well.
Create VendorInfo Data:
<Query> <Create> <VendorInfo> <vendorName>Phidget</vendorName> <vendorTitle>Sensor Provider</vendorTitle> <vendorAddress> <Street>123 TQL Way</Street> <City>Sunnyvale</City> <Zipcode>91234</Zipcode> </vendorAddress> <DeviceTypes>Sensors</DeviceTypes> <DeviceTypes>Actuators</DeviceTypes> </VendorInfo> </Create> </Query>
Query SensorVendorInfo DataModel
<Query> <Find> <SensorVendorInfo> <SensorVendorSysId ne=""/> </SensorVendorInfo> </Find> </Query>
SensorVendorInfo Find Result Contains data created in VendorInfo DataModel.
<Find Status="Success"> <Result> <SensorVendorInfo> <SensorVendorSysId>chag3vw7tcet7dvg2athubjwl2gvth73</SensorVendorSysId> <SensorVendorName>Phidget</SensorVendorName> </SensorVendorInfo> </Result> </Find>
Note that Data can be created in opposite direction as well i.e. Once created in SensorVendorInfo the common attributes will be available in VendorInfo as well.
<Create> <SensorVendorInfo> <SensorVendorName>Phidget2</SensorVendorName> </SensorVendorInfo> </Create> <!-- Lets Find from VendorInfo --> <Find> <VendorInfo> <VendorName ne=""/> </VendorInfo> </Find> <!-- Here is Find Result --> <Find Status="Success"> <Result> <VendorInfo> <VendorSysId>KP3XJHCLAAAAUAABBN4HSJE7</VendorSysId> <VendorName>Phidget2</VendorName> </VendorInfo> </Result> <Result> <VendorInfo> <VendorSysId>chag3vw7tcet7dvg2athubjwl2gvth73</VendorSysId> <DeviceTypes>Sensors</DeviceTypes> <DeviceTypes>Actuators</DeviceTypes> <VendorAddress> <City>Sunnyvale</City> <Street>123 TQL Way</Street> <Zipcode>91234</Zipcode> </VendorAddress> <VendorTitle>Sensor Provider</VendorTitle> <VendorName>Phidget</VendorName> </VendorInfo> </Result> </Find>
DataModel by picking Attributes from other defined DataModel + newly defined Attributes
DataModel can contain both cherry picked attributes as well as new attributes. Here SensorVendorInfo contains SensorTypes as new attribute of type string.
<DataModel Name="VendorInfo"> <Sid name="VendorSysId"/> <String name="VendorName"/> <String name="VendorTitle"/> <PostalAddress name="VendorAddress"/> <String Name="DeviceTypes" Cardinality="0..m"/> <Unique Name="UniqueVendorName" Value="VendorName"/> </DataModel> <DataModel name="SensorVendorInfo"> <Attribute name="SensorVendorSysId" value="VendorInfo.VendorSysId"/> <Attribute name="SensorVendorName" value="VendorInfo.VendorName"/> <String Name="SensorTypes Cardinality="0..m"/> </DataModel>
Let's create SensorVendorInfo now using Create TQL Query:
<Query> <Create> <SensorVendorInfo> <SensorVendorName>Phidget</SensorVendorName> <SensorVendorTitle>Sensor Provider</SensorVendorTitle> <SensorTypes>Temperature</SensorTypes> <SensorTypes>Light</SensorTypes> </SensorVendorInfo> </Create> </Query>
Let's do a Find on VendorInfo. We get the VendorInfo and VendorTitle data back.
<Query> <Find> <VendorInfo> <vendorSysId ne=""/> </VendorInfo> </Find> </Query>
Find VendorInfo Result
<Find Status="Success"> <Result> <VendorInfo> <VendorSysId>KNTR2FJXAAAAUAABA5OUP375</VendorSysId> <VendorName>Phidget</VendorName> </VendorInfo> </Result> </Find>
Selective Cherry picking using Constraint
In some cases we may want to selective pick attributes. For example, We only want Vendors with Sensor DeviceType. This can be achieved using Constraint.
In this case only Sensor DeviceTypes will be populated in SensorVendorInfo
<DataModel name="SensorVendorInfo"> <Attribute name="SensorVendorSysId" value="VendorInfo.VendorSysId"/> <Attribute name="SensorVendorName" value="VendorInfo.VendorName"/> <String Name="SensorTypes" Cardinality="0..m"/> <Constraint target="VendorInfo.DeviceTypes" eq="lit.Sensor"/> </DataModel>