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无人驾驶汽车大难题 人工智能同人的差距显著 - 资讯 - 清泛网 - 专注C/C++...
...出，在谷歌总部所在的山景城进行公路测试，正式学习该如何与普通汽车在公路上共同行进。谷歌还事先在无人驾驶车的“大脑”里加入了山景城的高精度虚拟地图，但这显然很难复制。从这一点上看，互联网公司宣称的“无人...
mysql Foreign key constraint is incorrectly formed error
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mysql error texts doesn't help so much, in my case, the column had "not null" constraint, so the "on delete set null" was not allowed
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Insert into a MySQL table or update if exists
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Check out REPLACE
http://dev.mysql.com/doc/refman/5.0/en/replace.html
REPLACE into table (id, name, age) values(1, "A", 19)
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Updating MySQL primary key
...-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f2341576%2fupdating-mysql-primary-key%23new-answer', 'question_page');
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拉里佩奇23条箴言帮你度过创业低谷 - 资讯 - 清泛网 - 专注C/C++及内核技术
...VCR也没能让电影院关门。
13。“如果让我用一句话总结如何改变世界，我会说，努力工作，为那些真正激动人心的事物。”
不是所有人都想要创造一辆无人驾驶车，或者清洁能源，或者解决十亿人的痛点。但在我内心，有一份...
How can I do an UPDATE statement with JOIN in SQL Server?
...Here are some ways to do it in ANSI/ISO (aka should work on any SQL DBMS), MySQL, SQL Server, and Oracle. Be advised that my suggested ANSI/ISO method will typically be much slower than the other two methods, but if you're using a SQL DBMS other than MySQL, SQL Server, or Oracle, then it may be the ...
What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...cally, a lot of dbms have been quite poor when it comes to handling joins (MySQL being a particularly noteworthy example). So n+1 has, often, been notably faster than a join. And then there are ways to improve on n+1 but still without needing a join, which is what the original problem relates to.
H...
How to change the foreign key referential action? (behavior)
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Example:
I have a UserDetails table refers to Users table:
mysql> SHOW CREATE TABLE UserDetails;
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:
`User_id` int(11) DEFAULT NULL,
PRIMARY KEY (`Detail_id`),
KEY `FK_User_id` (`User_id`),
CONSTRAINT `FK_User_id` FOREIGN KEY (`User_id`) REFERENCES `Users` (`User_id`)
:
:
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Unioning two tables with different number of columns
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