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https://issues.apache.org/jira/browse/FLINK-2828?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15258078#comment-15258078
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ASF GitHub Bot commented on FLINK-2828:
---------------------------------------
GitHub user fhueske opened a pull request:
https://github.com/apache/flink/pull/1939
[FLINK-2828] [tableAPI] Add TableSource interfaces for external tables.
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- [X] General
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build has passed
- Add CsvTableSource as a reference implementation for TableSources.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/fhueske/flink tableSource
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/1939.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1939
----
commit 06076767623895cc380d98543417feb3493396d9
Author: Fabian Hueske <[email protected]>
Date: 2016-04-25T17:00:09Z
[FLINK-2828] [tableAPI] Add TableSource interfaces for external tables.
- Add CsvTableSource as a reference implementation for TableSources.
----
> Add interfaces for Table API input formats
> ------------------------------------------
>
> Key: FLINK-2828
> URL: https://issues.apache.org/jira/browse/FLINK-2828
> Project: Flink
> Issue Type: New Feature
> Components: Table API
> Reporter: Timo Walther
> Assignee: Fabian Hueske
>
> In order to support input formats for the Table API, interfaces are
> necessary. I propose two types of TableSources:
> - AdaptiveTableSources can adapt their output to the requirements of the
> plan. Although the output schema stays the same, the TableSource can react on
> field resolution and/or predicates internally and can return adapted
> DataSet/DataStream versions in the "translate" step.
> - StaticTableSources are an easy way to provide the Table API with additional
> input formats without much implementation effort (e.g. for fromCsvFile())
> TableSources need to be deeply integrated into the Table API.
> The TableEnvironment requires a newly introduced AbstractExecutionEnvironment
> (common super class of all ExecutionEnvironments for DataSets and
> DataStreams).
> Here's what a TableSource can see from more complicated queries:
> {code}
> getTableJava(tableSource1)
> .filter("a===5 || a===6")
> .select("a as a4, b as b4, c as c4")
> .filter("b4===7")
> .join(getTableJava(tableSource2))
> .where("a===a4 && c==='Test' && c4==='Test2'")
> // Result predicates for tableSource1:
> // List("a===5 || a===6", "b===7", "c==='Test2'")
> // Result predicates for tableSource2:
> // List("c==='Test'")
> // Result resolved fields for tableSource1 (true = filtering,
> false=selection):
> // Set(("a", true), ("a", false), ("b", true), ("b", false), ("c", false),
> ("c", true))
> // Result resolved fields for tableSource2 (true = filtering,
> false=selection):
> // Set(("a", true), ("c", true))
> {code}
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