Add support for DuckDB

[m-feeser]

The elementary package for dbt does not currently support DuckDB. I am working on adding this support and wanted to create this issue to start the discussion as recommended in the CONTRIBUTIONS.md.

My initial plan is to address the errors that I'm seeing when running the current version of the package in an existing DuckDB project.

• Handle special characters
  • Create a duckdb__escape_special_chars() macro in the insert_rows.sql file
• Transaction handling
  • Create a duckdb__get_delete_and_insert_queries() macro in the delete_and_insert.sql file.
  • DuckDB does not like nested transactions, so this macro will not have the begin transaction block
• timeadd SQL dialect differences
  • Create a duckdb__edf_timeadd() macro in the timeadd.sql file. Use postgres style interval syntax

Are there any other areas I'm overlooking that need to be addressed?

I did notice there is a stale wip branch for DuckDB (duckdb_poc) which addresses materialization differences due to duckdb not supporting CTEs in views when it was created, but this is now supported by DuckDB.

I have never built integration tests for a dbt package, so I will likely need some guidance here.

[NoyaOffer]

Hey @m-feeser ! We'd love to discuss this further. Is it possible that you reach out via Slack or email? (noya@elementary-data.com)