Use of custom SQLite functions.

[dm-turing]

Hi,

My expertise: beginner - intermediate.

In my local env, I simply replaced "github.com/mattn/go-sqlite3" with "github.com/ncruces/go-sqlite3" and things just worked well without any issues. Awesome job!

Question though, does "github.com/ncruces/go-sqlite3" support custom functions yet?

For example, I wasn't able to execute the following snippet which seems to work with "github.com/mattn/go-sqlite3"

db.Exec("CREATE FUNCTION file_size(path TEXT) RETURNS INTEGER AS 'size(path)'")

I skimmed around the package and the closest was able to get to was sqlite_test.go.

What is the current workaround to implement SQLite custom functions? Does it involve using gorm?

Also please give some pointers to CONTRIBUTE for starters.

Thanks.

[ncruces]

SQLite does not support stored procedures (CREATE FUNCTION) so I'm not sure what you mean when you say mattn supports it.

You can create custom functions in Go (not in PL/SQL).

There are a bunch of examples in the repo, like this one:

go-sqlite3/func_test.go

Lines 80 to 82 in e2da469

	err = db.CreateFunction("upper", 1, sqlite3.DETERMINISTIC|sqlite3.INNOCUOUS, func(ctx sqlite3.Context, arg ...sqlite3.Value) {
	ctx.ResultRawText(bytes.ToUpper(arg[0].RawText()))
	})

This function receives a single TEXT argument, uppercases it with bytes.ToUpper, and returns it.

SQLite documentation for this is here: https://sqlite.org/appfunc.html

[dm-turing]

Thanks for the clarification. I didn't know custom function was reserved for go. SQLite is new to me as well.

That code snippet was generated by AI. I didn't test its functionality with mattn and simply trusted that it worked.