Wait for multiple statements to execute with R2DBC - spring-webflux

Question

I need to execute multiple statement with R2DBC but couldn't find useful DatabaseClient#inConnection* examples... So my function keeps getting out too early:
public Publisher<Person> groupStatements(DatabaseClient client, Person person) {
// yes, I know that's harsh, but hey! so is JPA's #ElementCollection
return client.sql("DELETE FROM persons_address WHERE person = :id")
.bind("id", person.getId())
.fetch().rowsUpdated()
.map(deleted -> {
// now recreate every relationship
GenericExecuteSpec statement = client.sql("INSERT INTO persons_address (person, address) VALUES (:person, :address)");
person.getOfficePlaces().forEach(address -> {
statement
.bind("person", person.getId()).bind("address", address.getId())
.fetch().rowsUpdated() // there we go AWOL
.subscribe(inserted -> {
// logging here
});
});
return person; //FIXME wait! need above grouped statements to complete
});
}
NB: I'm using H2 as a backend.
Thanks for any information!

Answer 1

I found a proper batch processing technic (here replacing the map/deleted section), but even got stuck because Statement#execute is returning a Publisher with only #subscribe method and I couldn't return from the chain. So I fed the beast with a few gearing
//DEBUG I couldn't figure out how to use labels! good enough
private static final String SQL_INSERT = "INSERT INTO persons_address (person, address) VALUES ($1, $2)";
...
.flatMap(deleted -> {
if (person.getOfficePlaces().isEmpty()) {
return Mono.just(person);
} else {
return client.inConnection(cnx -> {
Statement stmt = cnx.createStatement(SQL_INSERT);
person.getOfficePlaces().forEach(address -> {
stmt.bind(0, person.getId()).bind(1, address.getId()).add();
});
return Flux.from(stmt.execute()).last().map(dontcare -> person);
});
}