Asset contents or previews

You can see the contents or a preview of the contents of most data assets and some other types of assets on the Asset page of an asset in a catalog. In projects and other workspaces, you can see a preview of data assets that contain relational data.

Requirements and restrictions

You can view the contents or previews of assets under the following conditions and restrictions.

Required service
None. Previews are always visible.
Workspaces
You can view the preview or contents of assets in these workspaces:
  • Projects
  • Catalogs
  • Deployment spaces
Types of assets
  • Data assets from files
  • Connected data assets
  • COBOL copybooks
  • Dashboards
  • Data quality definitions
  • Logical data model asset types
  • Models
  • Model use cases
  • Notebooks
  • Physical data model asset types
  • Report asset types
  • Transformation script asset types
Required permissions
To see the asset contents or preview, these conditions must be true:
  • You have any collaborator role in the workspace.
  • In catalogs, you have access to the asset, either because the privacy setting for the asset is public, or you are a member of or the owner of the asset. See Controlling access to an asset.
  • In catalogs, you are not blocked by any data protection rules. See Data protection rule enforcement.
Restrictions for data assets
  • Assets can contain up to 5000 columns.

Previews of data assets

The previews of data assets show a view of the data.

Shows a data asset preview

You can see when the data in the preview was last fetched and refresh the preview data in projects and catalogs by clicking the refresh icon.

Requirements for data assets

The additional requirements for viewing previews of data assets depend on whether the data is accessed through a connection or from a file.

Connected data assets
You can see previews of data assets that are accessed through a connection if all these conditions are true:

  • You have access to the data asset and its associated connection. See Requirements and restrictions.

  • The data asset contains structured data. Structured data resides in fixed fields within a record or file, for example, relational database data or spreadsheets.

  • You have credentials for the connection:

    • For connections with shared credentials, the username in the connection details has access to the object at the data source.
    • For connections with personal credentials, you must enter your personal credentials when you see a key icon (the key symbol for private connections). This is a one-time step that permanently unlocks the connection for you. See Adding connections to projects.
Data assets from files
You can see previews of data assets from files if the following conditions are true:

  • You have access to the data asset. See Requirements and restrictions.

  • The file is stored in IBM Cloud Object Storage or in Cloud Pak for Data storage. For preview of text or image files from an IBM Cloud Object Storage connection to work, the connection credentials must include an access key and a secret key. If you’re using an existing Cloud Object Storage connection that doesn’t have these keys, edit the connection asset and add them. See IBM Cloud Object Storage connection.

  • The file type is supported. See File extensions and mime types of previewed files.

  • The content has UTF-8 encoding.

Masking and filtering in previews of data assets

The enforcement of data protection rules can result in masking data values or filtering rows from data assets. In a catalog, the asset owner always sees the original data asset without masking or filtering. In a project, all project collaborators see the asset the way it looks to the person who adds it from the catalog. After data protection rules or asset profiles are changed, rule enforcement can be delayed by up to one day until the asset previews are refreshed.

Masked data values
If data values in a column are masked by a data protection rule, you see a lock icon a lock icon next to the column name. Masked data can appear as similarly formatted values or as meaningless values. See Masking enforcement.
Filtered rows
If rows are filtered by a data protection rule, they don't appear in the preview. Under some circumstances, previews of filtered data assets are not available. See Previews might not be available.

Preview information for data assets

For structured data, the preview displays a limited number of rows and columns. The number of rows in the preview is limited to 1,000.

Previews show different information for different types of data assets and files:

Connected data assets
The preview shows column names, data types, and a subset of columns and rows of data.
Connected folder assets
The preview shows the files and subfolders, which you can also preview.
Relational data, CSV, Avro, partitioned data files, and Parquet files
The preview includes column names, data types, and a subset of columns and rows of data.
TSV files
The preview includes column names, data types, and a subset of rows of data.
PDF, text, JSON, HTML, and images
The preview shows the whole document. HTML files are supported in text format. Image formats that are supported are JPG, JPEG, PNG, GIF, BMP, and BMP1.
Microsoft Excel documents
The preview shows the first sheet.

File extensions and mime types of previewed files

These types of files that contain structured data have previews:

Structured data files
Extension Mime type
AVRO
CSV text/csv
CSV1 application/csv
JSON application/json
PARQUET
PARQ
TSV
TXT text/plain
XLSX application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
XLS application/vnd.ms-excel
XLSM application/vnd.ms-excel.sheet.macroEnabled.12

These types of image files have previews:
Image files
Extension Mime type
BMP image/bmp
GIF image/gif
JPG image/jpeg
JPEG image/jpeg
PNG image/png

These types of document files have previews:
Document files
Extension Mime type
HTML text/html
PDF application/pdf
TXT text/plain

Previews or contents of other types of assets in catalogs

Some other asset types show previews or contents on the Asset page of the asset in catalogs.

COBOL copybooks and data from z/OS
The Asset page shows the map metadata that is included with the IBM Data Virtualization Manager Data Mapping Facility on the mainframe computer.
Dashboards
The Asset page shows a snapshot of what the dashboard looks like. When you select to publish a dashboard to a catalog, you can choose to add screen captures of the dashboard with the dashboard file to the catalog. If a snapshot of the dashboard was added to the catalog, users can preview the snapshot before adding the dashboard from the catalog into another project.
Data quality definition
The Asset page shows rule logic that can be included in data quality rules.
Logical data model asset types
In catalogs, the Asset page shows entire logical data model hierarchy for all logical data model asset types. Users can see the context of each entity, group, relationship, or attribute in that hierarchy.
Models
In catalogs, the Asset page shows information about the model and the model training.
Model use cases
The Asset page shows information about models through each stage of the model lifecycle and details about the models and deployments that are tracked in the use case.
Notebooks
The Asset page shows the whole notebook.
Physical data model asset types
In catalogs, the Asset page shows entire physical data model hierarchy for all physical data model asset types. Users can see the context of each entity, group, relationship, or attribute in that hierarchy.
Report asset types
In catalogs, the Asset page shows the entire report hierarchy for report asset types, including parent, children, and siblings.
Transformation scripts
The Asset page shows the plain text version of the transformation expression.

Learn more

Parent topic: Asset types and properties