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is of a type that is invalid for use as a key column in an index
...g is that a varchar will take 4 bytes to determine the length of the item, meaning the actual limit needs to be varchar(896). Is this correct?
– mrmillsy
May 15 '14 at 11:31
2
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Hexadecimal To Decimal in Shell Script
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Dealing with a very lightweight embedded version of busybox on Linux means many of the traditional commands are not available (bc, printf, dc, perl, python)
echo $((0x2f))
47
hexNum=2f
echo $((0x${hexNum}))
47
Credit to Peter Leung for this solution.
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Removing all non-numeric characters from string in Python
...join(c for c in "abc123def456" if c.isdigit())
'123456'
The ''.join part means to combine all the resulting characters together without any characters in between. Then the rest of it is a list comprehension, where (as you can probably guess) we only take the parts of the string that match the con...
.prop() vs .attr()
... of the layer of magic jQuery stuck in front of attributes and properties, meaning jQuery developers will have to learn a bit about the difference between properties and attributes. This is a good thing.
If you're a jQuery developer and are confused by this whole business about properties and attr...
What are the differences between concepts and template constraints?
...tionship:
Concepts = Constraints + Axioms
To quickly summarise their meanings:
Constraint - A predicate over statically evaluable properties of a type. Purely syntactic requirements. Not a domain abstraction.
Axioms - Semantic requirements of types that are assumed to be true. Not statically...
What are “sugar”, “desugar” terms in context of Java 8?
...ut 'sugaring' and 'desugaring' more often in Java 8, what does these terms mean ? are they conceptual or syntactical.
4 Ans...
What is the documents directory (NSDocumentDirectory)?
... only (on a non-jailbroken device) runs in a "sandboxed" environment. This means that it can only access files and directories within its own contents. For example Documents and Library.
See the iOS Application Programming Guide.
To access the Documents directory of your applications sandbox, you ...
IIS AppPoolIdentity and file system write access permissions
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Thats right, which means the AppPool user's folder wouldn't get created if it wasnt true right? This is why they built it this way.....to prevent IIs from accessing and storing junk in windows/temp and all over the hard drive instead of a manag...
Getting the IP address of the current machine using Java
...rtual network devices, private network IP addresses, and so on.
What this means is that the IP address returned by InetAddress.getLocalHost() might not be the right one to use.
How can you deal with this?
One approach is to use NetworkInterface.getNetworkInterfaces() to get all of the known netw...
How to validate an email address in JavaScript
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@PaoloBergantino i mean that , why would i try to send a mail to check an obviously wrong mail address? even if i need to "be absolutely, positively sure that what the user entered is in fact an email" , i would only check the email addresses t...