用oracle写一个有触发器和函数两个过程带有表和表数据视图和索引的图书馆管理系统
时间: 2024-03-23 15:43:29 浏览: 72
oracle笔记函数,视图,存储过程,触发器
好的,下面是一个更完整的基于Oracle数据库的图书馆管理系统,包括一些触发器和函数,并带有表和表数据视图以及索引:
首先,我们需要创建以下表格:
1. 书籍表(books)
```
CREATE TABLE books(
book_id NUMBER PRIMARY KEY,
title VARCHAR(100),
author VARCHAR(50),
publisher VARCHAR(50),
publish_date DATE,
quantity NUMBER
);
```
2. 借阅记录表(borrow_records)
```
CREATE TABLE borrow_records(
borrow_id NUMBER PRIMARY KEY,
book_id NUMBER,
borrower VARCHAR(50),
borrow_date DATE,
return_date DATE
);
```
3. 用户表(users)
```
CREATE TABLE users(
user_id NUMBER PRIMARY KEY,
username VARCHAR(50),
password VARCHAR(50),
email VARCHAR(50)
);
```
接下来,我们可以创建以下触发器:
1. 在书籍表(books)中插入记录时,自动更新库存量(quantity)
```
CREATE TRIGGER update_quantity
AFTER INSERT ON books
FOR EACH ROW
BEGIN
UPDATE books
SET quantity = quantity + :new.quantity
WHERE book_id = :new.book_id;
END;
```
2. 在借阅记录表(borrow_records)中插入记录时,自动更新书籍库存量(quantity)和借阅次数
```
CREATE TRIGGER update_borrow_info
AFTER INSERT ON borrow_records
FOR EACH ROW
BEGIN
UPDATE books
SET quantity = quantity - 1
WHERE book_id = :new.book_id;
UPDATE books
SET borrow_count = borrow_count + 1
WHERE book_id = :new.book_id;
END;
```
3. 在借阅记录表(borrow_records)中更新记录时,自动更新归还日期(return_date)
```
CREATE TRIGGER update_return_date
BEFORE UPDATE OF borrow_date ON borrow_records
FOR EACH ROW
BEGIN
IF :new.return_date IS NULL THEN
:new.return_date := SYSDATE + 30;
END IF;
END;
```
接下来,我们可以创建以下函数:
1. 检查用户是否存在
```
CREATE OR REPLACE FUNCTION check_user(username IN VARCHAR, password IN VARCHAR)
RETURN BOOLEAN
AS
user_count NUMBER;
BEGIN
SELECT COUNT(*) INTO user_count
FROM users
WHERE username = check_user.username AND password = check_user.password;
IF user_count > 0 THEN
RETURN TRUE;
ELSE
RETURN FALSE;
END IF;
END;
```
接下来,我们可以创建以下表数据视图:
1. 查询借阅记录表(borrow_records)中借阅次数最多的书籍
```
CREATE VIEW top_borrowed_books AS
SELECT book_id, COUNT(*) AS borrow_count
FROM borrow_records
GROUP BY book_id
ORDER BY borrow_count DESC;
```
最后,我们可以创建以下索引:
1. 在书籍表(books)的书名(title)和作者(author)列上创建索引
```
CREATE INDEX books_title_author_idx
ON books(title, author);
```
以上是一个更完整的图书馆管理系统,带有表和表数据视图以及索引,并包括了触发器和函数来帮助管理该系统。您可以根据需要进行修改和扩展。
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