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分类： oracle
2019-12-17 09:58:46
choose three
the orders table has a primary key constraint on the order_id column.
the order_items table has a foreign key constraint on the order_id column,referencing the primary key of the orders table.
the constraint is defined with on delete cascade.
there are rows in the orders table with an order_total less than 1000.
which three delete statements execute successfully?
a) delete from orders where order_total<1000;
b) delete * from orders where order_total<1000;
c) delete orders where order_total<1000;
d) delete from orders;
e) delete order_id from orders where order_total<1000;
answer：acd
(解析：这个考的是语法题，属于低智商题目，因为定义外键的时候用了 delete cascade 选项，所以父表的行是可以删除。)