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What is an ORM, how does it work, and how should I use one? [closed]
...uction
Object-Relational Mapping (ORM) is a technique that lets you query and manipulate data from a database using an object-oriented paradigm. When talking about ORM, most people are referring to a library that implements the Object-Relational Mapping technique, hence the phrase "an ORM".
An ORM...
Is it possible for a computer to “learn” a regular expression by user-provided examples?
...ton, it is possible to learn some regular expressions by a program. Kearns and Valiant show some cases where it is not possible to learn a finite automaton. A related problem is learning hidden Markov Models, which are probabilistic automata that can describe a character sequence. Note that most mod...
Mutable vs immutable objects
...returning an array of strings from a method) but I'm having trouble understanding what the negative impacts are of this. What are the best practices around using mutable objects? Should you avoid them whenever possible?
...
jQuery: what is the best way to restrict “number”-only input for textboxes? (allow decimal points)
...
Update
There is a new and very simple solution for this:
It allows you to use any kind of input filter on a text <input>,
including various numeric filters. This will correctly handle
Copy+Paste, Drag+Drop, keyboard shortcuts, contex...
Why is extending native objects a bad practice?
... get a perfomance hit? Do they fear that somebody does it "the wrong way", and adds enumerable types to Object , practically destroying all loops on any object?
...
RabbitMQ and relationship between channel and connection
... a Channel are serialized, with only one thread being able to run a
command on the Channel at a time. Even so, applications should prefer
using a Channel per thread instead of sharing the same Channel across
multiple threads.
There is no direct relation between Channel and Queue. A Channel ...
JPA and Hibernate - Criteria vs. JPQL or HQL
What are the pros and cons of using Criteria or HQL ? The Criteria API is a nice object-oriented way to express queries in Hibernate, but sometimes Criteria Queries are more difficult to understand/build than HQL.
...
JUnit: how to avoid “no runnable methods” in test utils classes
... I don't think it would help, because he moved to JUnit 4.4 and that should not matter.
– guerda
Mar 23 '09 at 7:46
2
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What exactly is Spring Framework for? [closed]
...The problem
For example, suppose you need to list the users of the system and thus declare an interface called UserLister:
public interface UserLister {
List<User> getUsers();
}
And maybe an implementation accessing a database to get all the users:
public class UserListerDB implements...
What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...
Braces ($var vs. ${var})
In most cases, $var and ${var} are the same:
var=foo
echo $var
# foo
echo ${var}
# foo
The braces are only needed to resolve ambiguity in expressions:
var=foo
echo $varbar
# Prints nothing because there is no variable 'varbar'
echo ${var}bar...