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Asset previews
Asset previews

Asset previews

If you have the required permissions, you can see a preview of the contents of many types of data assets and some types of operational assets in projects and catalogs. Previews include a limited set of rows in a tabular data asset. The number of rows that are included depends on the amount of data that is contained in the asset. For data assets from files, only files with specific file extensions and mime types have previews.

Permissions to view previews

To see an asset preview, these conditions must be true:

  • 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.
  • You are not blocked by any data protection rules. If you are the owner of the asset, you cannot be blocked by data protection rules.
  • If the asset has an associated connection, these conditions must also be true:
    • You are not blocked from accessing the connection by any data protection rules.
    • The username in the connection details has access to the object at the data source.

If you see a shield icon a shield icon next to the column name of a relational data asset, it means that the data in the column is masked by a data protection rule. Data protection rules can mask data by masking the original values with similarly formatted values, or by substituting the values and format of the data with meaningless values. Within a catalog, the owner of the asset is not affected by data protection rules and always sees the original values. Within a project, all project collaborators see the asset the way it looks to the person who adds it from the catalog.

Preview content for types of assets, files, and data

The content that you see in a preview depends on the type of asset, file, or data.

Relational data, CSV, Avro, partitioned data files, and Parquet files The preview includes column names, data types, data classes, and a subset of rows of data. Data classes identify the type of content in the column. Data classes are inferred automatically as part of the asset profile. For connected data, you can see when the data in the preview was last fetched from the connection and refresh the preview data in projects and catalogs by clicking Refresh.

Data connections marked with a key icon (the key symbol for private connections) are locked. If you are authorized to preview the data source, you are asked to enter your personal credentials the first time you select it. This is a one-time step that permanently unlocks the connection for you. See Adding connections to projects.

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.

Microsoft Excel documents The preview shows the first sheet.

Folder assets The preview shows the files and subfolders, which you can also preview.

Notebooks The preview shows the whole notebook.

Models The preview shows information about the model.

Dashboards The preview 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.

COBOL copybooks and data from z/OS Previews of data assets that are pulled from virtual tables provide you with access to the data on the mainframe computer. COBOL copybook assets reflect the map metadata included with the IBM Data Virtualization Manager Data Mapping Facility on the mainframe computer.

Preview of data assets that were added as managed assets by using the Watson Data API is not supported.

Preview data from a connection

When you preview data from a connection to a data source other than IBM Cloud Object Storage, only structured data is supported. Structured data resides in fixed fields within a record or file. For example, relational database data or spreadsheets.

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.

File extensions and mime types of previewed files

These types of files that contain structured data have previews:

Structured data files
Extension Mime type
csv text/csv
csv1 application/csv
json application/json
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

Parent topic: Finding and viewing an asset in a catalog