View Schema Metadata in the Catalog Browser

Every Confluent Cloud for Apache Flink® workspace has a catalog browser, a tree in the left panel that lets you browse the catalogs, databases, and objects available to your workspace. The catalog browser is backed by the INFORMATION_SCHEMA catalog, so the metadata it displays comes directly from Confluent Cloud for Apache Flink, not from Apache Kafka® or Schema Registry.

Because the catalog browser reads from Flink’s own metadata, it can show you information that isn’t available anywhere else in Confluent Cloud Console, including:

The Flink SQL data type of each column, translated from the underlying topic schema, for example VARCHAR(2147483647) instead of a raw Schema Registry type
System columns, such as $rowtime, alongside your user-defined columns
Whether a column is nullable
Which column, if any, is the table’s PRIMARY KEY
The expression that defines a table’s watermark
All WITH options configured on a table, view, model, tool, or agent

Note

The metadata queries that populate the catalog browser run as lightweight, hidden Flink SQL statements. They don’t consume CFUs, so browsing the catalog tree and opening object details doesn’t add to your Flink bill.

Prerequisites

You need the following prerequisites to use Flink in Confluent Cloud Console.

Access to Confluent Cloud.

Browse the catalog tree

Log in to Confluent Cloud Console and open a Flink SQL workspace. For steps to create a workspace, see Quick Start with Cloud Console.
In the catalog browser, expand an environment, which represents a catalog, and a cluster, which represents a database.

The tree shows a section for each kind of catalog object:
- Tables
- Materialized tables
- Views
- Models
- Agents
- Tools
- Functions
- External tables
A section appears empty until you expand it for the first time, which triggers the metadata query for that object type. If a database has no objects of a given type yet, the section shows a prompt to create one, for example Create a view.
Click a section, like Tables, to expand it and list the objects it contains.

View column metadata

Click a table, view, or other object in the catalog browser’s tree.

A details panel opens below the tree, showing the object’s name and an expandable Schema section that lists every column, along with its Flink SQL data type.

System columns, like $rowtime, are listed alongside user-defined columns and are marked with a distinct icon. A column that’s part of the table’s PRIMARY KEY is marked with a key icon.
Hover over a column to see a tooltip with more metadata:

Type
the column’s fully qualified Flink SQL data type

Nullable
whether the column allows NULL values

Primary key
shown when the column is part of the table’s primary key

System
shown for system columns like $rowtime

Watermark
for a watermarked column, the expression that defines the watermark, for example SOURCE_WATERMARK()

View object options

The catalog browser’s details panel includes an Options section, below Schema, that lists the object’s WITH options as key-value pairs. Examples include connector, changelog.mode, and any connector-specific options like rows-per-second.

Click Options to expand or collapse the list. If the panel is too narrow to show a long option key or value, drag the panel’s edge to resize it.

Generate a DESCRIBE statement

Instead of typing a DESCRIBE statement by hand, you can generate one directly from the catalog browser.

Click an object in the catalog browser’s tree to open its details panel.
Click the Describe this table icon next to the object’s name.

A new cell is added to the workspace with a generated statement, for example:
```
DESCRIBE EXTENDED `examples`.`marketplace`.`orders`;
```
Click Run to see the object’s extended metadata as query results, including its columns, WITH options, and constraints.