Working on a SurrealDB driver

[senpro-ingwersenk]

Hello there!

Yesterday I crunched out a database/sql[/driver] interface for Go, for surrealDB. It works and I am currently expanding on the test coverage to make sure that everything works as intended. But, the primary motivation for writing this in the first place, was so that I could use GORM. If there is one thing lacking for SurrealDB, then it's tooling. Cool to have these AI features and advanced table opterations and whatnot - but, without good tooling, it's just... fancy. x)

so, I decided to forego their official Go module (it uses CBOR and is half-broken) and write my own. And now, I am all over the GORM docs, trying to find out what I need to implement in order to write my driver - well, Dialector.

A few things I noticed while looking at the MySQL one that I must implement differently, but do not know how to, yet:

• SurrealDB does come with it's own version of prepared statements, in the form of parameters that can be sent alongside a query. For example, sending the RPC message {"id":"abc", "method":"query", ["SELECT * from $tbl", { "tbl": "mytable" }]} will already do the variable substition. My driver also implements that by using the let method for prepared statements, or inlines them as shown in this message. But, how do I do that for GORM? The interface specifies BindVarTo(...). How exactly am I supposed to work with this? Store the variables in the current connection object and then pick it up later at query time?
• There are a good bit of different and even additional statements compared to standart SQL. For instance, there are a few ways to insert data - the quickes one is basically CREATE person VALUES <jsonObject>. The only notable "type" would be when referencing other table entries (record IDs) - those are simply not quoted. So I need to deal with that in a special way. Those record IDs also make up the primary key by default, by the way. Each record has an ID field like "ID": mytable:someidentifier (the string is quoted in the JSON reply, but technically it shouldn't be.) Where, or how, do I handle them? Looking at the custom clauses - like the LIMIT one given in the docs - this only seems to apply to certain expressions. However, features like REINDEX, UPSERT, LIVE and KILL - let alone all the event features - are custom queries. They are rather optional, but for completeness-sake, I would love to implement them properly. Where, and how, do I do that?

I am still figuring most of the interfaces out - but I am under a wee bit of time pressure to finish this project sooner rather than later...so I have to go the hybrid approach of asking here, reading the docs, and building into the void an dhope things stick x) Apologies for the lil' bit of chaos.

Thank you very much and kind regards!

[senpro-ingwersenk]

I have made a few advances here - and perhaps a little "critique": Every clause.* has a Name() string method that is not part of the interface. However, those names are actually used in db.ClauseBuilders (part of gorm.Config) to overwrite certain clauses.

Further, the statements (or clauses, I guess?) are split quite deeply. Overwriting INSERT isn't going to be given the columns that are to be written - this will fall to another clause, VALUES, instead. I wish those names were consts - if only for semantics, this would help spot them in the documentations at pkg.go.dev much more quickly (case in point).

I have yet to figure out callbackConfig and sit down and write all of the custom statements.

If I find the time, I would love to document the process of implementing a driver - where would I send the PR for that, in fact? to the gorm.io repo? Or somewhere else?

Thanks!