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What is the difference between Left, Right, Outer and Inner Joins?
...students without lockers and some lockers that have no students assigned.
For the sake of this example, lets say you have 100 students, 70 of which have lockers. You have a total of 50 lockers, 40 of which have at least 1 student and 10 lockers have no student.
INNER JOIN is equivalent to "show me...
Why use multiple columns as primary keys (composite primary key)
...que.
The alternative is to use a generated (non-intelligent) primary key, for example in this case OrderDetailId. But then you would not always see the relationship as easily. Some folks prefer one way; some prefer the other way.
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Do SVG docs support custom data- attributes?
...lly correct, they omit the fact that SVG provides an alternative mechanism for data-*. SVG allows any attribute and tag to be included, as long as it doesn't conflict with existing ones (in other words: you should use namespaces).
To use this (equivalent) mechanism:
use mydata:id instead of data...
How to create a protocol with methods that are optional?
...ls defined in the iPhone SDK, such as the UIActionSheetDelegate protocol for example.
5 Answers
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CSS: How to have position:absolute div inside a position:relative div not be cropped by an overflow:
...sition: absolute to be positioned relative to the outer box. But remember: for box #3 to be positioned relative to box #2, box #2 just need to be positioned. With this change, we get:
And here is the full code with this change:
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en...
Does Git warn me if a shorthand commit ID can refer to 2 different commits?
...SHA1, because of int minimum_abbrev = 4 in environment.c. (Thanks @devnull for pointing that out!)
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Import pandas dataframe column as string not int
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Thank you for the comments. I also had to use dypte=str AND keep_default_na = False so that null values weren't nan.
– Ross117
Jul 23 at 18:22
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Detect all changes to a (immediately) using JQuery
...e current value of element
elem.data('oldVal', elem.val());
// Look for changes in the value
elem.bind("propertychange change click keyup input paste", function(event){
// If value has changed...
if (elem.data('oldVal') != elem.val()) {
// Updated stored value
ele...
How do I see active SQL Server connections?
...rprise. I want to see any active SQL Server connections, and the related information of all the connections, like from which IP address, connect to which database or something.
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Storing time-series data, relational or non?
I am creating a system which polls devices for data on varying metrics such as CPU utilisation, disk utilisation, temperature etc. at (probably) 5 minute intervals using SNMP. The ultimate goal is to provide visualisations to a user of the system in the form of time-series graphs.
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