beginExclusive method
Returns a new QueryExecutor
that, when first opened, takes an exclusive
lock over this
executor and prevents queries from running until it is
closed.
The difference between this and beginTransaction is that this does not
start a database transaction. The QueryExecutor
returned by
beginExclusive can be used to start a transaction with
beginTransaction.
Implementation
@override
QueryExecutor beginExclusive() {
return _ExclusiveExecutor(this);
}