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Introduction

The metadata structure of object types has to be defined in the schema. In this definition, properties are referenced that should be connected to the object type. Each property is in turn defined in the schema by the specification of its attributes. The properties can be referenced or not referenced in object type definitions, but their attributes are fixed and cannot be modified. The required attribute is the only exception as it can be overwritten by a propertyReference in object type definitions. This makes it possible to decide for each property individually whether it is required in every single object type definition or not. Since schema structures can even be changed at runtime, yuuvis® Momentum offers a high flexibility in terms of document lifecycle management.

Requirements

To work through this tutorial, the following is required:

• Set-up yuuvis® Momentumsystem (see minikube setup, for example)
• A user with read and write permissions on a document type in the system (see tutorial for permissions)

Overwriting the required Attribute of Properties

All property definitions in the schema need the specification of the required attribute. Its boolean value decides if the corresponding property is mandatory (true) or optional (false) for an object.  However, the value of the required attribute can be overwritten by a propertyReference in object type definitions.

Property Definition

In an import management system, documents may be imported with less properties than they will have lateron in their lifecycle. A freshly imported object for example does not necessarily have an editor. Later in the document lifecycle, this information may be required. By overwriting the required attribute of the editor property, it is possible to use the same property throughout the entire lifecycle.

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<propertyStringDefinition>
    <id>editor</id>
    <propertyType>string</propertyType>
    <cardinality>single</cardinality>
    <required>true</required>
</propertyStringDefinition>

Overwriting Using a Document Type Definition

In a document type definition, a propertyReference can be used to set a value for the required attribute of a property. This value can be different from the value specified in the property definition. In this case, the value of the required attribute will be specified in the document type definition.

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<propertyStringDefinition>
    <id>editor</id>
    <propertyType>string</propertyType>
    <cardinality>single</cardinality>
    <required>true</required>
</propertyStringDefinition>

<typeDocumentDefinition>
    <id>imported1</id>
    <baseId>system:document</baseId>
    <propertyReference required="false">editor</propertyReference>
    <contentStreamAllowed>allowed</contentStreamAllowed>
</typeDocumentDefinition>

Overwriting Using a Secondary Object Type Definition

An alternative option to reference a property in an object type definition is to include a floating secondary object type. In the secondary object type definition, a propertyReference can be used to set a value for the required attribute for a property. The required attribute value specified in the original property definition is again overwritten.

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<propertyStringDefinition>
    <id>editor</id>
    <propertyType>string</propertyType>
    <cardinality>single</cardinality>
    <required>true</required>
</propertyStringDefinition>

<typeDocumentDefinition>
    <id>imported2</id>
    <baseId>system:document</baseId>
    <contentStreamAllowed>allowed</contentStreamAllowed>
    <secondaryObjectTypeId static="false">noeditor</secondaryObjectTypeId>
</typeDocumentDefinition>
 
<typeSecondaryDefinition>
    <id>noeditor</id>
    <baseId>system:secondary</baseId>
    <propertyReference required="false">editor</propertyReference>
</typeSecondaryDefinition>

Handling Multiple Property References

In a document type definition, it is possible to set a value for the required attribute of a property, and additionally include multiple secondary object types specifying the required attribute for the same property as well. If at least one definition implies required=true, this attribute will be true for every document of the corresponding type. The value true dominates over false regardless of the location of the propertyReference.

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If a document of type imported3 has none of the two secondary object types, the editor property is optional.
If a document of type imported3 has the secondary object type noeditor, nothing changes. The editor property is still optional.
But if a document of type imported3 has the secondary object type witheditor, the property editor is mandatory in this object.

Summary

This tutorial gave an introduction into the possibilities provided by the option of overwriting the required attribute of properties. Since this topic plays a role in the handling of the schema, also the following pages might be interesting to you.

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