Add support for MS SQL Server

[unusualmutant]

Currently this DB is not supported as a source, but is widely used. Would be great to have the option of reading from MS SQL Server tables as well.

[labianchin]

Thanks for raising this!

There has been a PR #32 , but it did not went further. I don't think there is any plan currently to add support for it.

When designing for MS SQL Server support we need to consider:

1. Design to interoperate with other DBeam features (e.g. --partition, --limit, -queryParallelism, ...) in a maintainable way (i.e. avoiding if isMsSQLServer() everywhere).
2. Add some good test coverage on this feature so that we can keep confidence to evolve DBeam. It would be great to have some e2e tests covering Google Cloud SQL and Google Dataflow offering, but the reality is that would be quite some investment.

[rulle-io]

The issue with having a mssql jdbc library not included into dbeam package can be solved by providing a option to add(load) a 3rd-party library at runtime.