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 (). 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. 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.

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.
• The amount of data is limited to 800 KB. The more columns the data asset has, the fewer rows that appear in the preview.

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: