twalthr commented on a change in pull request #15428:
URL: https://github.com/apache/flink/pull/15428#discussion_r604979251
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File path:
flink-table/flink-table-api-java-bridge/src/main/java/org/apache/flink/table/api/bridge/java/StreamTableEnvironment.java
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@@ -202,15 +209,152 @@ static StreamTableEnvironment create(
/**
* Converts the given {@link DataStream} into a {@link Table}.
*
- * <p>The field names of the {@link Table} are automatically derived from
the type of the {@link
- * DataStream}.
+ * <p>Column names and types of the {@link Table} are automatically
derived from the {@link
+ * TypeInformation} of the {@link DataStream}. If the outermost record's
{@link TypeInformation}
+ * is a {@link CompositeType}, it will be flattened in the first level.
{@link TypeInformation}
+ * that cannot be represented as one of the listed {@link DataTypes} will
be treated as a
+ * black-box {@link DataTypes#RAW(Class, TypeSerializer)} type. Thus,
composite nested fields
+ * will not be accessible.
+ *
+ * <p>Since the DataStream API does not support changelog processing
natively, this method
+ * assumes append-only/insert-only semantics during the stream-to-table
conversion. Records of
+ * type {@link Row} must describe {@link RowKind#INSERT} changes.
+ *
+ * <p>By default, the stream record's timestamp and watermarks are not
propagated unless
Review comment:
True, but for clear semantics the current default makes more sense.
Otherwise we don't know how to name and where to put the time attribute. Also,
not every data stream has a time attribute. We cannot know this in advance.
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