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https://issues.apache.org/jira/browse/FLINK-8240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16296546#comment-16296546
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Timo Walther commented on FLINK-8240:
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Thanks for your response [~wheat9]. We need to decide how the syntax for
{{CREATE EXTERNAL TABLE}} will look like. It could look more like Hive or more
like the unified interace of this issue. But in any case such a statement would
compile down to the unified interface. We won't support every combination of
connector/encoding but with this abstraction we don't need to expose things
like a {{KafkaAvroTableSource}}, {{KafkaJsonTableSource}}, etc. anymore. From
an API level we have a clear separation that might (or might not) also separate
components internally in the future.
Btw not all tables need to be built with a factory. For now, we will keep the
builders inside every table source (like {{CsvTableSource.builder()}}). This is
also needed because you cannot express everything as a string property. The
factories will use the builders to create the table sources.
> Create unified interfaces to configure and instatiate TableSources
> ------------------------------------------------------------------
>
> Key: FLINK-8240
> URL: https://issues.apache.org/jira/browse/FLINK-8240
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Timo Walther
> Assignee: Timo Walther
>
> At the moment every table source has different ways for configuration and
> instantiation. Some table source are tailored to a specific encoding (e.g.,
> {{KafkaAvroTableSource}}, {{KafkaJsonTableSource}}) or only support one
> encoding for reading (e.g., {{CsvTableSource}}). Each of them might implement
> a builder or support table source converters for external catalogs.
> The table sources should have a unified interface for discovery, defining
> common properties, and instantiation. The {{TableSourceConverters}} provide a
> similar functionality but use an external catalog. We might generialize this
> interface.
> In general a table source declaration depends on the following parts:
> {code}
> - Source
> - Type (e.g. Kafka, Custom)
> - Properties (e.g. topic, connection info)
> - Encoding
> - Type (e.g. Avro, JSON, CSV)
> - Schema (e.g. Avro class, JSON field names/types)
> - Rowtime descriptor/Proctime
> - Watermark strategy and Watermark properties
> - Time attribute info
> - Bucketization
> {code}
> This issue needs a design document before implementation. Any discussion is
> very welcome.
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