Best way to add Snowflake's TRANSIENT keyword (for CREATE)?

[ttzhou]

First off - thank you and contributors for the hard work put into such a great tool. It's inspiring.

Discussion point:

Looking to add TRANSIENT as a valid keyword in Snowflake dialect. Right now, something like CREATE TRANSIENT TABLE AS ... fails with ParseError.

First time attempting to contribute here, so wanted to ask/understand best way to go about this before opening a PR.

Think it makes sense to add TRANSIENT as a TokenType and KEYWORDS in token module, but not quite sure about:

• whether I should create a new Create for Snowflake dialect with "transient" : False added to the arg_types, or just add to the "root" file
• whether to change the create_sql in base generator module, or subclass into Snowflake specific Generator
• similarly for _parse_create in base parser module vs. Snowflake specific one.

Any guidance appreciated. Thanks for any help.

[georgesittas]

Hello! I'll try to answer your questions inline:

whether I should create a new Create for Snowflake dialect with "transient" : False added to the arg_types, or just add to the "root" file

I think the best approach here is to just add the "transient": False argument in expressions.py. We don't have per-dialect expression or statement type definitions, so that parsing and transpiling is made easier.

whether to change the create_sql in base generator module, or subclass into Snowflake specific Generator

Better put it in the base generator module, because this is a core method and the SQL code will be pretty much identical, except for the TRANSIENT part.

similarly for _parse_create in base parser module vs. Snowflake specific one.

Again, similar logic applies as above, so better in the base parser. We're trying to have the base parser be as lenient as possible because SQLGlot tries to be a superset of other dialects.

Feel free to play around and open a PR and we can discuss this in more detail. I think this feature is a good starting point.