Copilot commented on code in PR #9908:
URL: https://github.com/apache/gravitino/pull/9908#discussion_r2776950106
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docs/lakehouse-generic-iceberg-table.md:
##########
@@ -0,0 +1,178 @@
+---
+title: "Iceberg table support"
+slug: /iceberg-table-support
+keywords:
+- lakehouse
+- iceberg
+- metadata
+- generic catalog
+license: "This software is licensed under the Apache License version 2."
+---
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+## Overview
+
+This document describes how to use Apache Gravitino to manage Iceberg tables
in a Generic Lakehouse
+Catalog. The current release supports **external Iceberg tables**
(metadata-only registration).
+Managed Iceberg tables will be supported in a future release.
+
+## Table Management
+
+### Supported Operations
+
+For Iceberg tables in a Generic Lakehouse Catalog, the following table
summarizes supported
+operations:
+
+| Operation | Support Status |
+|-----------|----------------|
+| List | ✅ Full |
+| Load | ✅ Full |
+| Alter | ✅ Full |
+| Create | ✅ External |
+| Register | ✅ External |
+| Drop | ✅ External |
+| Purge | ❌ Not supported |
+
+:::note Feature Limitations
+- **Managed tables:** Not supported yet. A managed Iceberg table mode (with
commit support) will be
+ added in the next release.
+- **Purge:** Not supported for external Iceberg tables because Gravitino does
not manage the
+ underlying data.
+:::
+
+### External vs Managed Tables
+
+- **External table (current release)**:
+ - Gravitino stores only metadata.
+ - `drop` removes Gravitino metadata only.
+ - `purge` is not supported.
+ - Use this mode to register existing Iceberg tables.
+
+- **Managed table (next release)**:
+ - Gravitino will manage Iceberg table metadata updates and commit lifecycle.
+ - `drop` and `purge` behavior will include data lifecycle management.
+
+### Table Properties
+
+Required and optional properties for Iceberg tables in a Generic Lakehouse
Catalog:
+
+| Property | Description
| Default | Required | Since Version |
+|------------|-----------------------------------------------------------------------------|---------|----------|---------------|
+| `format` | Table format. Must be `iceberg`.
| (none) | Yes | 1.1.0 |
+| `location` | Storage path for the Iceberg table (warehouse or table root).
| (none) | Conditional* | 1.1.0 |
+| `external` | Must be `true` for external Iceberg tables.
| false | Yes | 1.1.0 |
+
+**Location Requirement:** Must be specified at catalog, schema, or table
level. See
+[Location Resolution](./lakehouse-generic-catalog.md#key-property-location).
+
+### Table Operations
+
+Table operations follow standard relational catalog patterns. See
+[Table
Operations](./manage-relational-metadata-using-gravitino.md#table-operations).
+
+The following sections provide examples for working with Iceberg tables.
+
+#### Creating an External Iceberg Table
+
+<Tabs groupId='language' queryString>
+<TabItem value="shell" label="Shell">
+
+```shell
+curl -X POST -H "Accept: application/vnd.gravitino.v1+json" \
+ -H "Content-Type: application/json" -d '{
+ "name": "iceberg_table",
+ "comment": "Example external Iceberg table",
+ "columns": [
+ {
+ "name": "id",
+ "type": "integer",
+ "comment": "Primary identifier",
+ "nullable": false
+ }
+ ],
+ "properties": {
+ "format": "iceberg",
+ "external": "true",
+ "location": "/tmp/iceberg_catalog/schema/iceberg_table"
+ }
+}'
http://localhost:8090/api/metalakes/test/catalogs/generic_lakehouse_catalog/schemas/schema/tables
+```
+
+</TabItem>
+<TabItem value="java" label="Java">
+
+```java
+Catalog catalog = gravitinoClient.loadCatalog("generic_lakehouse_catalog");
+TableCatalog tableCatalog = catalog.asTableCatalog();
+
+Map<String, String> tableProperties = ImmutableMap.<String, String>builder()
+ .put("format", "iceberg")
+ .put("external", "true")
+ .put("location", "/tmp/iceberg_catalog/schema/iceberg_table")
+ .build();
+
+tableCatalog.createTable(
+ NameIdentifier.of("schema", "iceberg_table"),
+ new Column[] {
+ Column.of("id", Types.IntegerType.get(), "Primary identifier",
+ true, false, null)
Review Comment:
In the “Creating an External Iceberg Table” examples, the Shell snippet sets
the `id` column as `nullable: false`, but the Java snippet uses `Column.of(...,
true, false, null)` which makes the column nullable. Please align these
examples (e.g., use `false` for the nullable argument) so the two language
examples describe the same schema semantics.
```suggestion
false, false, null)
```
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