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Does MySQL ignore null values on unique constraints?
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Yes, MySQL allows multiple NULLs in a column with a unique constraint.
CREATE TABLE table1 (x INT NULL UNIQUE);
INSERT table1 VALUES (1);
INSERT table1 VALUES (1); -- Duplicate entry '1' for key 'x'
INSERT table1 VALUES (NULL);
INSER...
What characters can be used for up/down triangle (arrow without stem) for display in HTML?
...POINTING TRIANGLE
▼ - U+25BC BLACK DOWN-POINTING TRIANGLE
▴ - U+25B4 SMALL BLACK UP-POINTING TRIANGLE
▾ - U+25BE SMALL BLACK DOWN-POINTING TRIANGLE
For ▲ and ▼ use ▲ and ▼ respectively if you cannot include Unicode characters directly (use UTF-8!).
Note that the fo...
Specifying colClasses in the read.csv
... the read.csv function in R. In my data, the first column "time" is basically a character vector while the rest of the columns are numeric.
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Git diff between current branch and master but not including unmerged master commits
I want a diff of all changes in a branch that is not merged to master yet.
3 Answers
3...
jQuery to loop through elements with the same class
...length to get length of that elements ul li?
– techie_28
Sep 21 '12 at 6:09
17
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What's an object file in C?
...t from the compilation phase. It's mostly machine code, but has info that allows a linker to see what symbols are in it as well as symbols it requires in order to work. (For reference, "symbols" are basically names of global objects, functions, etc.)
A linker takes all these object files and comb...
jQuery Event : Detect changes to the html/text of a div
I have a div which has its content changing all the time , be it ajax requests , jquery functions , blur etc etc.
12 An...
How exactly does the python any() function work?
...st of some items. If it contained [0, False, '', 0.0, [], {}, None] (which all have boolean values of False) then any(lst) would be False. If lst also contained any of the following [-1, True, "X", 0.00001] (all of which evaluate to True) then any(lst) would be True.
In the code you posted, x > ...
Sorting related items in a Django template
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I added an alternate solution for you. It should allow you the flexibility you need.
– tawmas
Jun 30 '11 at 22:39
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Difference between UTF-8 and UTF-16?
...c. occupy one byte which is identical to US-ASCII representation. This way all US-ASCII strings become valid UTF-8, which provides decent backwards compatibility in many cases.
No null bytes, which allows to use null-terminated strings, this introduces a great deal of backwards compatibility too.
UT...