CREATE OR REPLACE TRIGGER trigger_borrowing_limitREFERENCING NEW ROW AS NROWFOR EACH ROW
WHEN SELECT COUNT(*) FROM Borrowing WHERE RETURN_DATE IS NULL AND NROW.ID = Borrowing.ID
我有一个名为Borrowing的表,其中包含列id、borrow_date和duration。我想创建一个函数来检查状态。如果有人想借这本书,他们会给出两个参数(v_book和v_date)。v_date DATE) RETURN VARCHAR2;v_borrow date;SELECT duration INTO v_duration FROM BorrowingWHERE id = v_book;
SELECT borrow_date INTO v_borrow FROM Borrowing</e