A metadata schema defines the layout of the metadata properties page for assets within Adobe Experience Manager (AEM) Assets that use the particular schema. Metadata properties include title, description, MIME types, tags, and so on.
Use the Metadata Schema Forms editor to modify existing schemas or add a custom metadata schema for assets.
Edit various metadata properties under the Basic and Advanced tabs. However, you cannot modify the asset type in the Properties page.
To modify the MIME type for an asset, use a custom metadata schema form or modify an existing form. See Editing Metadata Schema Forms for more information. If you modify a metadata schema for a certain MIME-type of assets, the layout for the current MIME-type and all asset subtypes are modified. For example, modifying a jpeg schema under default/image only modifies the metadata layout (asset properties) for the IMAGE/JPEG MIME-type of assets. However, if you edit the default schema, your changes modify the metadata layout for all types of assets.
To view a list of forms/templates, click the AEM logo and then navigate to Tools > Assets > Metadata Schemas.
AEM provides the following templates out of the box:
The following child forms inherit the properties of the default form:i. image: Schema form for assets with the MIME type "image", for example, image/jpeg, image/png, and so on.The "image" form has the following child form templates:a. jpeg: Schema form for assets with sub type jpeg.b. tiff: Schema form for the assets with sub type tiff.ii. application: Schema form for assets with MIME type "application", for example application/pdf, application/zip, and so on.a. pdf: Schema form for assets with sub type pdf.iii. video: Schema form for assets with MIME type "video", such as video/avi, video/mp4 and so on.
- default: The base metadata schema form for assets.
- forms: This schema form relates to Adobe Experience Manager Forms.
- contentfragment: Schema form for content fragments.
To view the child forms of a schema form, click the schema form name.
You can edit a newly-added or existing metadata schema form. The metadata schema form contains content derived from it's parent, including:
- Form items within tabs.
You can map/configure these form items to a field within a metadata node in the CRX repository.
You can add new tabs or form items to the metadata schema form. The tabs and form items derived from the parent are in the locked state. You cannot alter them at the child level.
The Build Form tab lists form items that you use in your schema form. The Settings tab provides the attributes of each item that you select in the Build Form tab. The following table lists the form items available in the Build Form tab:
|Section Header||Add a section heading for a list of common components.|
|Single Line Text||Add a single line text property. It is stored as a string.|
|Multi Value Text||Add a multi value text property. It is stored as a string array.|
|Number||Add a number component.|
|Date||Add a date component.|
|Dropdown||Add a dropdown list.|
|Standard Tags||Add a tag.|
|Hidden Field||Add a hidden field. It is sent as a POST parameter when the asset is saved.|
|Asset Referenced By||Add this component to view list of assets referenced by the asset.|
|Asset Referencing||Add to display a list of assets that reference the asset.|
|Products References||Add to show the list of products linked with the asset.|
|Asset Rating||Add to display options for rating the asset.|
To edit the properties of a metadata component on the form, click the component and edit all or a subset of the following properties in the Settings tab.
Field Label: The name of the metadata property that is displayed on the asset's Properties page.
Map to Property: The value of this property provides the relative path/name to the asset node where it is saved in the CRX repository. It starts with "./" because indicating that the path is under the asset's node.
The following are the valid values for this property:
- ./jcr:content/metadata/dc:title: Stores the value at the asset's metadata node as the property dc:title.
- ./jcr:created: Displays the jcr property at the asset's node. If you configure these properties on view properties, we recommend that you mark them as Disable Edit, because they are protected. Otherwise, the error "Asset(s) failed to modify" occurs when you save the asset's properties.
There should not be any space in the property path you provide in this field. Otherwise, the component is not displayed properly in the metadata schema form.
Placeholder: Use this property to provide the user any relevant information regarding the metadata property.
Required: Use this property to mark a metadata property as mandatory on the Properties page.
Disable Edit: Use this property to make a metadata property uneditable on the Properties page.
Show Empty Field In Read Only: Mark this property to display a metadata property on the Properties page even if it has no value. By default, when a metadata property has no value, it is not be listed on the Properties page.
Show list ordered: Use this property to display an ordered list of choices
Choices: Use this property to specify choices in a list
Description : Use this property to add a short description for the metadata component.
Class: Object class the property is associated with.
Delete icon Click this icon to delete a component from the schema form.
Only the Hidden Field component does not have the attributes Map to Property, Placeholder, Required, Disable edit and Show Emplty Field in Read Only properties. It has the attributes Name, Value, Field Label, and Description. The values for the Hidden Field component are sent as a POST parameter whenever the asset is saved. It is not be saved as metadata for the asset.
If you select the Required option, you can search for assets missing mandatory metadata. From the Filters & Options panel, expand the Metadata Validation predicate and select the Invalid option. The search results display assets missing mandatory metadata that you configured through the schema form.
Instead of specifying properties for the options in the Settings tab, you can define the options in a JSON file by specifying corresponding key-value pairs. Specify the path of the JSON file in the JSON Path field.
The schema editor lets you add or delete a tab. The default schema form includes the Basic and Advanced tabs, by default.
Click + to add a new tab on a schema form. By default, the new tab has the name "Unnamed-1." You can modify the name from the Settings tab.
Click X to delete a tab.
AEM lets you delete custom schema forms only. It does not let you delete the default schema forms/templates. However, you can delete any custom changes in these forms.
To delete a form, select a form and click the Delete icon.
After you delete custom changes to a default form, the Lock icon reappears before it on the Metadata Schema interface to indicate that the form reverted to its default state.
You cannot delete the out of the box metadata schema forms in AEM Assets.
In addition to the default forms, you can add custom forms for assets of various MIME types. Create a new form under the appropriate form type. For example, to add a new template for the image/png subtype, created the form under the "image" forms. The title for the schema form is the subtype name. In this case, the title is "png."
You can use an existing template for a different MIME type. For example, use the image/jpeg form for assets of MIME type image/png.
In this case, create a new node at /etc/dam/metadataeditor/mimetypemappings in the CRX repository. Specify a name for the node and define the following properties:
|exposedmimetype||Name of the existing form to be mapped||String||image/jpeg|
|mimetypes||List of MIME types that use the form defined in the exposedmimetype attribute||String||image/png|
|Schema Form||MIME type(s)|
|video/avi||video/avi, video/msvideo, video/x-msvideo|
The Metadata Schema feature is available to administrators only. However, administrators can provide access to non administrators by modifying some permissions.
The non administrator should have Create, Modify, and Delete permissions on the /apps folder.
AEM Assets lets you define a variant of a metadata schema and apply it to a specific folder.
For example, you can define a variant of the default metadata schema and apply it to a folder. When you apply the modified schema, it overrides the original default metadata schema that is applied to assets within the folder.
Only assets uploaded to the folder on which this schema is applied will conform to the modified metadata defined in the variant metadata schema.
Assets in other folders where the original schema is applied continue to conform to metadata defined in the original schema.
Metadata inheritance by assets is based on the schema that is applied to the first-level folder in the hierarchy. In other words, if a folder does not contain subfolders, the assets within the folder inherit the metadata from the schema applied to the folder.
If the folder has a subfolder, the assets within the subfolder inherit the metadata from the schema applied at the subfolder level if a different schema is applied at the subfolder level. If, however, no schema or the same schema is applied at the subfolder level, the subfolder assets inherit the metadata from the schema applied at the parent folder level.
You can define mandatory fields at a folder level, which is enforced on assets that are uploaded to the folder. If you upload assets with missing metadata for the mandatory fields defined earlier, a visual indication for missing metadata appears on the assets in the Card view.