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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
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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
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.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
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浙公网安备 33010602011771号