Executes a one-off SQL command and returns the first row received, or null
if none. Useful for the case where you expect a (possibly empty) result set,
and you're either only expecting one row, or only care about the first row.
Use this method when you will use the same command repeatedly.
It will throw if the specified command does not produce a result set.
If there are long data items among the expected result columns you can specify
that they are to be subject to chunked transfer via a delegate.
Executes a one-off SQL command and returns the first row received, or null if none. Useful for the case where you expect a (possibly empty) result set, and you're either only expecting one row, or only care about the first row.
Use this method when you will use the same command repeatedly. It will throw if the specified command does not produce a result set.
If there are long data items among the expected result columns you can specify that they are to be subject to chunked transfer via a delegate.