The biggest misconception with solar covers or rings is that they are meant to heat the pool. While these products may raise the pool temperature, they do so by reducing heat loss (mainly at night). Solar blankets should not be left on a pool during daylight hours, and at the very least, they should be removed for a 4-8 hours during the day for the pool to breathe.
ALTER DATABASE ... SET autocommit = 1 causes an implicit commit if the value was 0. All these statements cause an implicit commit before execution. This means that, even if the statement fails with an error, the transaction is committed. Some of them, like CREATE TABLE ... SELECT, also cause a commit immediatly after execution.
You misunderstand. That code is temporarily changing the default value property. only until the form is closed. To make a permanent change the form would have to. be opened in design view when the code is executed. This applies to any change. you make to a form or report using code when not in design view. It is never. permanent with a few exceptions like the OrderBy or Filter properties.