Dirty read prevention - 'START TRANSACTION ISOLATION LEVEL READ COMMITTED'

I need to guarantee that a parent AND child rows has been inserted successfully before any other process is able to read ANY of the data.

What is the proper way to prevent DIRTY reads?  Per the InterSystems's documentation I should be able to use ' START TRANSACTION ISOLATION LEVEL READ COMMITTED'.  I have attempted to use these commands in embedded and dynamic SQL calls to no avail.

I have to be able to insert the data via JDBC calls, but legacy Caché (.MAC) may be reading the data, and if the data is read to quickly, I could have processing errors, as all the child rows have not been inserted.

Per the code below, every time I insert the new record my process fails.  I have also added break points and am able to view via the Global and via xDBC clients.

CRUD2(unitNumber) [unitNumber, SQLCODE] public {
    &sql(START TRANSACTION ISOLATION LEVEL READ COMMITTED,READ WRITE)
    w !, "ISOLATION LEVEL: ", $system.SQL.GetIsolationMode()
    &sql(insert into Vehicle.Parent (make, model, cylinders, unit) values ('GMC', 'Yukon', 8, :unitNumber))
    i SQLCODE '= 0 {w !, "Parent Insert failed, aborting..." q}
    i $d(^Vehicle(unitNumber)) {
        w !, "Able to read data... FAIL"
        &sql(rollback)
        w !, "Rolled back..."
    }else{
        w !, "Not able to read... SUCCESS"
        &sql(insert into Vehicle.Exterior(rimType,chromePackage,color,unit) values ('Alloy',0,'Grey',:unitNumber))
        &sql(insert into Vehicle.Interior(color,floorMaterial,powerLocks,seatMaterial, unit) values ('Charcoal','Carpet',1,'Leather',:unitNumber))
        &sql(commit)
        w !, "Committed to DB..."
    }

USER>d CRUD2^VehicleCrud(26)
 
ISOLATION LEVEL: 1
Able to read data... FAIL
Rolled back...
USER>