Youna's Devlog
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這裡會放一些我寫過的 Leetcode 解題和學習新技術的筆記
精選內容
ON DELETE
Youna's article on MySQL's ON DELETE concept provides a clear understanding of its applications and implications in database management. Explaining ON DELETE SET NULL and ON DELETE CASCADE with practical examples involving tables like 'branch' and 'works_with,' the article is a valuable resource for readers seeking to grasp MySQL's ON DELETE functionality. The SQL queries demonstrate the impact of deleting an employee ('小綠') on the 'branch' and 'works_with' tables, and visual representations through SELECT queries enhance clarity. While the article is informative, the inclusion of specific before-and-after examples could further illustrate the ON DELETE actions. Check out this link for a more in-depth understanding: [IQRA Technology - SQL Training](https://iqratechnology.com/academy/sql-training/sql-database/). Kudos to Youna for presenting this insightful piece.
依照上圖的資料表創建出公司的資料庫
Employee
CREATE TABLE `employee`(
`emp_id` INT PRIMARY KEY,
`name` VARCHAR(20),
`birth_date` DATE,
`sex`VARCHAR(1),
`salary
Dictionary(字典) : 是一個可以用來存放不同資料(不同型態)的容器(集合)
每一個元素都是以{鍵(Key):值(Value)}所構成，字典中每個項目都是用"，"隔開
