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How to design a database for User Defined Fields?
...rformance is the primary concern, I would go with #6... a table per UDF (really, this is a variant of #2). This answer is specifically tailored to this situation and the description of the data distribution and access patterns described.
Pros:
Because you indicate that some UDFs
have values for a...
Why are floating point numbers inaccurate?
...ted a lot like scientific notation: with an exponent and a mantissa (also called the significand). A very simple number, say 9.2, is actually this fraction:
5179139571476070 * 2 -49
Where the exponent is -49 and the mantissa is 5179139571476070. The reason it is impossible to represent some de...
ExpressJS - throw er Unhandled error event
...
Such a common error really deserves a better error message.
– Tamlyn
Jul 10 '14 at 21:15
...
Get all elements but the first from an array
...ontent-policy\"\u003e(content policy)\u003c/a\u003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true,enableSnippets:true
});
...
Hidden features of HTML
...ge Contains Both Secure and Non-Secure Items" error message in IE, keeping all your asset requests within the same protocol.
Caveat: When used on a <link> or @import for a stylesheet, IE7 and IE8 download the file twice. All other uses, however, are just fine.
...
Trying to fix line-endings with git filter-branch, but having no luck
...r gitattributes now documents another approach for "fixing" or normalizing all the line endings in your project. Here's the gist of it:
$ echo "* text=auto" >.gitattributes
$ git add --renormalize .
$ git status # Show files that will be normalized
$ git commit -m "Introduce end-of-line ...
Get an object properties list in Objective-C
...turn nil;
}
NSMutableDictionary *results = [[[NSMutableDictionary alloc] init] autorelease];
unsigned int outCount, i;
objc_property_t *properties = class_copyPropertyList(klass, &outCount);
for (i = 0; i < outCount; i++) {
objc_property_t property = properties[i...
Is it possible to change icons in Visual Studio 2012?
...e and it looks fine.
One way to hack around the icon inversion is to edit all the extracted images to add a single cyan pixel in the top right corner of each icon in the image map. This will exclude them from the inversion process. I haven't tried this though because I ran into issues early on when...
What is a columnar database?
...an easy fashion).
How do they differ from relational databases?
They generally differ from traditional (row-oriented) databases with regards to ...
performance...
storage requirements ...
ease of modification of the schema ...
...in specific use cases of DBMSes.
In particular they offer advanta...
Can I have multiple primary keys in a single table?
...re UNIQUE, taken together, and also NOT NULL. Thus, specifying values for all the columns of any candidate key is enough to determine that there is one row that meets the criteria, or no rows at all.
Candidate keys are a fundamental concept in the relational data model.
It's common practice, if m...