Improve JDBC connector type mapping docs

[tangjiangling]

Now we are trying to explain in a big table what is the type mapping relationship between Trino and different connectors, which will cause a problem for users: is this mapping relationship for both read and write operations?

So we should explain in the type mapping document what the type mapping relationship is for Trino read operations and what the type mapping is for Trino write operations, and I think the MySQL type mapping document is a good example to refer to.

The following is a list of JDBC connectors that require improved type mapping documentation:

• [ ] ClickHouse - #13578
• [ ] Druid
• [ ] SingleStore(MemSQL)
• [x] MySQL
• [ ] MariaDB
• [x] Oracle
• [ ] Phoenix4/5
• [x] PostgresSQL - #13118
• [ ] Redshift
• [x] SQL Server - #11564

[tangjiangling]

And I also observed that there are some JDBC connectors that do not have type mapping tests (e.g. Druid, Redshift), which is also needed to be added.

[tangjiangling]

cc @ebyhr @hashhar For the non-JDBC connector, I don't have much context, so I didn't list it, but I personally think it's also necessary to have type mapping documentation as well as tests.

[ebyhr]

@tangjiangling Yes, it would be nice if we can improve other connectors' documentation as well.

[mosabua]

Just for reference .. @jhlodin is working on this across all connectors. We might also have a generic section where we explain more.

[tlblessing]

Oracle PR https://github.com/trinodb/trino/pull/13659

[tangjiangling]

@tlblessing Added to the list, thanks for your contribution.

[tangjiangling]

Close this issue and thank you all for making this happen.

Since Redshift still has no type mapping tests, no type mapping documentation will be added for now (see https://github.com/trinodb/trino/pull/13832#issuecomment-1282942980).

[hashhar]

Thanks a lot @tangjiangling for kicking this off and seeing it to completion.