摘要: Every movie needs a director and every rented movie needs to exist in the store. How do we make sure something in another table exists before insertin 阅读全文
posted @ 2017-05-31 21:08 Zhentiw 阅读(181) 评论(0) 推荐(0)
摘要: Let’s say we have a bank. Our bank wants to give each account for each user a unique name, for instance, “Personal” or “Checking.” How can we make sur 阅读全文
posted @ 2017-05-31 21:03 Zhentiw 阅读(199) 评论(0) 推荐(0)
摘要: .share() is an alias for .publish().refCount(). So if the source is not yet completed, no matter how many subscribers subscribe to the source, they sh 阅读全文
posted @ 2017-05-31 18:27 Zhentiw 阅读(756) 评论(0) 推荐(0)