Use qualified names on DELETE selections

[nuno-faria]

Which issue does this PR close?

• N/A.

Rationale for this change

The logical plan for Deletions was not using qualified column names for the selections, which meant they were not being pushed down to the table. Conversely, Updates were already using qualified names, so this was not a problem for them.

What changes are included in this PR?

• Added qualified column names to the selections when processing a DELETE.
• Updated integration tests.
• Added delete.slt since there were no sqllogictests for the DELETE operator (follows a similar structure to update.slt).

Are these changes tested?

Yes.

Are there any user-facing changes?

No.

[comphead]

Thanks @nuno-faria this is good to have although I'm afraid for now UPDATE/DEL DML are not yet supported

Btw @alamb this is prob a good question is there a place in roadmap to support UPDATE/DELETE DMLs? for a single machine engine it might be beneficial. DuckDB supports it

[alamb]

Thanks @nuno-faria -- this PR makes sense to me -- the improved test coverage is especially nice 👌

[alamb]

Btw @alamb this is prob a good question is there a place in roadmap to support UPDATE/DELETE DDLs? for a single machine engine it might be beneficial. DuckDB supports it

TLDR is I don't think there is any standard way to support UPDATE/DELETE in any of the formats that DataFusion comes with(parquet, json, avro, jason)

My understanding is that the DML planning support in Datafusion is used for:

1. Formats (e.g. iceberg) that do have support for update/delete
2. Systems (e.g. some proprietary db systems) that can support update/delete

This is something we should probably add to the DataFusion documentation somewhere 🤔

[comphead]

Agree, I was mostly thinking about in memory dataset or Iceberg as it also supports DML, lets wait for the real use case to come