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Why was the switch statement designed to need a break?
...
2. Antipatterns: Doesn't provide "clean" tagged unions, one of the two fundamental data-representation idioms of assembly. (Knuth, vol 1, ch 2) Instead, "untagged unions," a non-idiomatic hack. This choice has hobbled the way people think of data for decades. And NUL-termi...
Set NOW() as Default Value for datetime datatype?
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As of MySQL 5.6.5, you can use the DATETIME type with a dynamic default value:
CREATE TABLE foo (
creation_time DATETIME DEFAULT CURRENT_TIMESTAMP,
modification_time DATETIME ON UPDATE CURRENT_TIMESTAMP
)
Or even...
How do you create a read-only user in PostgreSQL?
I'd like to create a user in PostgreSQL that can only do SELECTs from a particular database. In MySQL the command would be:
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Update statement with inner join on Oracle
...sn't valid in Oracle. You can do this:
UPDATE table1 SET table1.value = (SELECT table2.CODE
FROM table2
WHERE table1.value = table2.DESC)
WHERE table1.UPDATETYPE='blah'
AND EXISTS (SELECT table2.CODE
FROM table2
...
What are the differences between struct and class in C++?
...ate by
default. Members of a class defined
with the keywords struct or union
are public by default.
Additional difference: the keyword class can be used to declare template parameters, while the struct keyword cannot be so used.
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MIN/MAX vs ORDER BY and LIMIT
...oks like MIN() is able to simply pluck the smallest value from the index ('Select tables optimized away' and 'NULL' rows) whereas the SORT and LIMIT still needs needs to do an ordered traversal of the index (106,000 rows). The actual performance impact is probably negligible.
It looks like MIN() i...
Web安全测试之XSS - 更多技术 - 清泛网 - 专注C/C++及内核技术
...马等。
作为测试人员，需要了解XSS的原理，攻击场景，如何修复。 才能有效的防止XSS的发生。
阅读目录
XSS 是如何发生的
HTML Encode
XSS 攻击场景
XSS漏洞的修复
如何测试XSS漏洞
HTML Encode 和URL Encode的区别
浏览器中的XSS...
SQL WHERE ID IN (id1, id2, …, idn)
... But how would you pass the list of ids that you need? (Seeing you can't select a range or something like that).
– raam86
Oct 18 '16 at 14:32
1
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SQL join: selecting the last records in a one-to-many relationship
... want to get a list of all customers along with their last purchase in one SELECT statement. What is the best practice? Any advice on building indexes?
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Rename a table in MySQL
Renaming a table is not working in MySQL
16 Answers
16
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