The “Rule of One” states that you install one new goal at a time.
这个理论注重的是一次你只确定一个新的目标。
2
Prepared statements are so useful that PDO actually breaks the rule set out in Goal number 4: if the driver doesn't support prepared statements, PDO will emulate them.
You apply that goal to application URLs by connecting the transaction class to a work class (that maps to a set of URLs) through the creation of a routing rule.