Hi, dev.
I want to start a discussion about the FLIP-273: Improve Catalog API to Support ALTER TABLE syntax[1]. The motivation of the FLIP is the current Catalog API is difficult for some Catalog to alter the table. For example, the Catalog only exposes void alterTable(ObjectPath tablePath, CatalogBaseTable newTable, boolean ignoreIfNotExists) now. The main problem of this API is it requires the Catalog, e.g.`JDBCCatalog` to compare the difference between the new `CatalogTable`and the original CatalogTable, then generate the SQL to alter the table in the external system. However, the `ALTER TABLE` syntax already told the Catalog the differences. With the proposal, the Catalog developer can easily support the `ALTER TABLE` syntax. Looking forward to feedback on that proposal. Best, Shengkai [1] https://cwiki.apache.org/confluence/display/FLINK/FLIP-273%3A+Improve+the+Catalog+API+to+Support+ALTER+TABLE+syntax
