摘要： 以下为控制结构需要注意的：在条件判断比较多的情况下，推荐使用CASE语句代替IF/ELSE控制The value of a Boolean expression can be assigned directly to a Boolean variable. Youcan replace the first IF statement with a simple assignment:overdrawn := new_balance < minimum_balance;case语句:The ELSE clause isoptional. However, if you omit the EL 阅读全文

摘要： Overview of Predefined PL/SQL DatatypesA scalar type has no internal components. It holds a single value, such as a number orcharacter string.A composite type has internal components that can be manipulated individually, suchas the elements of an array.A reference type holds values, called pointers, 阅读全文