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https://issues.apache.org/jira/browse/FLINK-5280?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15772758#comment-15772758
]
ASF GitHub Bot commented on FLINK-5280:
---------------------------------------
Github user wuchong commented on a diff in the pull request:
https://github.com/apache/flink/pull/3039#discussion_r93756487
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/sources/TableSource.scala
---
@@ -19,21 +19,32 @@
package org.apache.flink.table.sources
import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.table.api.TableEnvironment
-/** Defines an external table by providing schema information, i.e., field
names and types.
+/** Defines an external table by providing schema information and used to
produce a
+ * [[org.apache.flink.api.scala.DataSet]] or
[[org.apache.flink.streaming.api.scala.DataStream]].
+ * Schema information consists of a data type, field names, and
corresponding indices of
+ * these names in the data type.
+ *
+ * To define a TableSource one need to implement
[[TableSource.getReturnType]]. In this case
+ * field names and field indices are deducted from the returned type.
+ *
+ * In case if custom field names are required one need to implement both
+ * [[TableSource.getFieldsNames]] and [[TableSource.getFieldsIndices]].
*
* @tparam T The return type of the [[TableSource]].
*/
trait TableSource[T] {
- /** Returns the number of fields of the table. */
- def getNumberOfFields: Int
-
/** Returns the names of the table fields. */
- def getFieldsNames: Array[String]
-
- /** Returns the types of the table fields. */
- def getFieldTypes: Array[TypeInformation[_]]
+ def getFieldsNames: Array[String] = {
+ TableEnvironment.getFieldInfo(getReturnType)._1
+ }
+
+ /** Returns the indices of the table fields. */
+ def getFieldsIndices: Array[Int] = {
+ getFieldsNames.indices.toArray
--- End diff --
I think this could be simplified to
`getReturnType.getArity.indices.toArray`.
> Extend TableSource to support nested data
> -----------------------------------------
>
> Key: FLINK-5280
> URL: https://issues.apache.org/jira/browse/FLINK-5280
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Affects Versions: 1.2.0
> Reporter: Fabian Hueske
> Assignee: Ivan Mushketyk
>
> The {{TableSource}} interface does currently only support the definition of
> flat rows.
> However, there are several storage formats for nested data that should be
> supported such as Avro, Json, Parquet, and Orc. The Table API and SQL can
> also natively handle nested rows.
> The {{TableSource}} interface and the code to register table sources in
> Calcite's schema need to be extended to support nested data.
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