I am inserting a record into a "header" table and several records into a "details" table within the same SP.
My question is quite simple. Is a transaction implied within a SP when inserting into multiple tables within the same SP?

Something like this:

CREATE Procedure sp_Preset AS
INSERT INTO Header (..) VALUES (...)
INSERT INTO Detail (..) VALUES (...)
INSERT INTO Detail (..) VALUES (...)
INSERT INTO Detail (..) VALUES (...)

What if the 2nd insert into the Detail table fails for whatever reason, will all the above inserts be rolled back automatically or do I have to wrap this all into a transaction?

Einar