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Primary key or Unique index?
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What is a unique index?
A unique index on a column is an index on that column that also enforces the constraint that you cannot have two equal values in that column in two different rows. Example:
CREATE TABLE table1 (foo ...
Putting license in each code file? [closed]
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@Esko: Can you please post a sample? I don't know what you have written for the copyright. Thanks.
– Joan Venge
May 11 '09 at 16:46
6
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How to 'git pull' into a branch that is not the current one?
...git pull in the main folder to synchronise it with origin/master. This is what I am trying to avoid.
– Malvineous
Sep 25 '13 at 5:41
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“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
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In case you want to see what this all means, here is a blow-by-blow of everything:
CREATE TABLE `users_partners` (
`uid` int(11) NOT NULL DEFAULT '0',
`pid` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`uid`,`pid`),
KEY `partner_user` (`pid`,...
Best way to merge two maps and sum the values of same key?
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Scalaz has the concept of a Semigroup which captures what you want to do here, and leads to arguably the shortest/cleanest solution:
scala> import scalaz._
import scalaz._
scala> import Scalaz._
import Scalaz._
scala> val map1 = Map(1 -> 9 , 2 -> 20)
map1: sca...
DbEntityValidationException - How can I easily tell what caused the error?
I have a project that uses Entity Framework. While calling SaveChanges on my DbContext , I get the following exception:
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What are all the valid self-closing elements in XHTML (as implemented by the major browsers)?
What are all the valid self-closing elements (e.g. ) in XHTML (as implemented by the major browsers)?
13 Answers
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Uniq by object attribute in Ruby
What's the most elegant way to select out objects in an array that are unique with respect to one or more attributes?
14 An...
Is nested function a good approach when required by only one function? [closed]
...t;> a
<function do_it at 0xb772b304>
>>> a()
4
Is this what you were looking for? It's called a closure.
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When would you use a WeakHashMap or a WeakReference?
...hing that I've never seen an implementation of so I'm trying to figure out what the use case for them is and how the implementation would work. When have you needed to use a WeakHashMap or WeakReference and how was it used?
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