Dear Community, FLIP-79 Flink Function DDL Support <https://docs.google.com/document/d/16kkHlis80s61ifnIahCj-0IEdy5NJ1z-vGEJd_JuLog/edit#>
This proposal aims to support function DDL with the consideration of SQL syntax, language compliance, and advanced external UDF lib registration. The Flink DDL is initialized and discussed in the design <https://docs.google.com/document/d/1TTP-GCC8wSsibJaSUyFZ_5NBAHYEB1FVmPpP7RgDGBA/edit#heading=h.wpsqidkaaoil> [1] by Shuyi Chen and Timo. As the initial discussion mainly focused on the table, type and view. FLIP-69 [2] extend it with a more detailed discussion of DDL for catalog, database, and function. Original the function DDL was under the scope of FLIP-69. After some discussion <https://issues.apache.org/jira/browse/FLINK-7151> with the community, we found that there are several ongoing efforts, such as FLIP-64 [3], FLIP-65 [4], and FLIP-78 [5]. As they will directly impact the SQL syntax of function DDL, the proposal wants to describe the problem clearly with the consideration of existing works and make sure the design aligns with efforts of API change of temporary objects and type inference for UDF defined by different languages. The FlLIP outlines the requirements from related works, and propose a SQL syntax to meet those requirements. The corresponding implementation is also discussed. Please kindly review and give feedback. Best Regards Peter Huang
