Support for CREATE TABLE statement

[tevelee]

Hi. I was wondering whether you have plans to support CREATE TABLE statements as well. I see a bunch of use-cases in pointfreeco/sharing-grdb#34 where the SQL is typed manually with the new #sql macro.
It seems to me that every necessary piece of information is available on the Columns type generated by the @Table macro for this statement to be supported.

[natemann]

I think this was discussed in the Slack channel, and the conclusion was it would not be ideal. Since migrations / create statements are a snapshot of history, how would this work if you delete a column, or change a column's name.

[mbrandonw]

Hi @tevelee, we don't have any docs on this, but we probably should.

In our view, table definitions, indices, triggers, etc., should all be created with SQL strings (you can even use our #sql macro to get the benefits of some light linting). This is because a migration is a version of your schema at a frozen moment in time, whereas your Swift data type is the idealized version of your schema right now. Once a migration has been shipped and run on user devices it should never be edited again, and therefore it is not appropriate to use the statically known symbols to create tables.

And we also feel that the chance of typos in table definitions is pretty low. It's far more obvious when a table definition is wrong than when a query is wrong since it's most likely the very first thing that executes when your app starts. And further, table definitions do not allow for bindings, and so there's no risk of SQL injection (though #sql always protects against that).

[tevelee]

That makes sense, thank you. I think the type safety benefits would be great for those statements as well. I would create a single use @table RemindersSchemaV1 just for the benefit of being able to create a generated table definition and indices. I understand if you don't, but thankfully your library is extensible.

[mbrandonw]

Yeah, it should hopefully be possible to create your own table definition tools using the tools in our library. And if you try it out and run into any problems, let us know!