Rethinkdb，继续：确保一个ReQL语句中的表和索引

Question

I need to ensure existence of table(s) upon application startup.

I also want to create secondary index on the table if table does not exist and needs to be created.

It is easily done in Go but I would like to do it in ReQL in one statement. So I came up with this:

func ensureTableIndex(ses *r.Session, name string, index string) (err error) {
    err = r.TableList().Contains(name).Do(r.Branch(r.Row, r.Expr(nil), r.Do(func() r.Term {
        return r.TableCreate(name).Do(func() r.Term {
            return r.Table(name).IndexCreate(index)
        })
    }))).Exec(ses)
    return
}

Seems to pass the test.

My question is whether this is a correct/efficient way to do table and index creation in one go? Is using ReQL Do() function the correct way to sequence multiple write commands?

Thanks

Answer 1

Yeah, do is the normal way you sequence operations in ReQL. The r.Do as the third argument to branch is superfluous, though; you can just put the tableCreate call there directly.