Asset contents or previews
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.
Workspaces
You can view the preview or contents of assets in these workspaces:
- Projects
Types of assets
The following types of assets have previews:
- Data assets from files
- Connected data assets
- Models
- Notebooks
Required permissions
You can see the asset contents or preview with any collaborator role in the workspace.
Restrictions for data assets
Additional requirements apply to connected data assets and data assets from files. See Requirements for data assets.
Previews are not available for data assets that were added as managed assets by using the Watson Data API.
Previews of data assets
The previews of data assets show a view of the data.
You can see when the data in the preview was last fetched and refresh the preview data by clicking the refresh icon.
- Requirements for data assets
- Preview information for data assets
- File extensions and mime types of previewed files
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.
-
The content has UTF-8 encoding.
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.
Structured data
For structured data, the preview shows column names, a subset of columns and rows of data. The supported formats for structured data include relational data, CSV, TSV, Avro, Microsoft Excel documents, and partitioned Parquet data (for IBM Cloud Object Storage and S3 connections). Microsoft Excel documents show the first sheet.
Assets from file based connections like Apache Kafka and Apache Cassandra are not supported.
Unstructured data
Unstructured data files must be stored in IBM Cloud Object Storage to have previews.
For these unstructured data files, the preview shows the whole document: Text, JSON, HTML, PDF, and images. HTML files are supported in text format. Images stored in IBM Cloud Object Storage support JPG, JPEG, PNG, GIF, BMP, and BMP1.
For connected folder assets, the preview shows the files and subfolders, which you can also preview.
File extensions and mime types of previewed files
These types of files that contain structured data have previews:
| Extension | Mime type |
|---|---|
| AVRO | |
| CSV | text/csv |
| CSV1 | application/csv |
| PARQ | |
| TSV | |
| 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:
| 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:
| Extension | Mime type |
|---|---|
| HTML | text/html |
| application/pdf | |
| TXT | text/plain |
Learn more
Parent topic: Asset types and properties