1.查看某用户下所有对象的信息: SELECT owner, object_type, status, COUNT(*) count# FROM all_objects where owner='xxx' GROUP BY owner, object_type, status order by ; 2.查看表行数(多个表)(需先分析表): select 'analyze table '|| table_name||' compute statistics;' from user_tables;
继承 类的继承机制使得子类可以继承父类中定义的方法,拥有父类的财产,比如有一个Animal的类作为父类,它有一个eat方法: class Animal(object): def __init__(self): print("Animal 构造函数调用!") def eat(self): print("Animal is eatting!") 写两个子类,Cat和Dog类,继承自Animal类,声明方法是在定义子类的时候在子类的括号内写上父类Animal: class