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Why does calling a method in my derived class call the base class method?
...
You can imagine, that a class, when instantiated, is nothing more than a table of pointers, pointing to the actual implementation of its methods. The following image should visualize this pretty well:
Now there are different ways, a method can be defined. Each behaves different when it is used ...
Why are ToLookup and GroupBy different?
...happens when you call ToLookup on an object representing a remote database table with a billion rows in it?
The billion rows are sent over the wire, and you build the lookup table locally.
What happens when you call GroupBy on such an object?
A query object is built; end of story.
When that quer...
Which annotation should I use: @IdClass or @EmbeddedId
...ingle property, and it permits the reuse of the @Embeddable class in other tables.
The next most natural approach is the use of the @EmbeddedId tag. Here, the primary key class cannot be used in other tables since it is not an @Embeddable entity, but it does allow us to treat the key as a
single a...
Scheduling R Script
..., to run scheduler first install below packages
install.packages('data.table')
install.packages('knitr')
install.packages('miniUI')
install.packages('shiny')
install.packages("taskscheduleR", repos = "http://www.datatailor.be/rcube", type =
"source")
After installing go to
**TOOLS...
How to change the style of alert box?
...
the custom alert in the answer is not compatable to the native alert. The native alert and prompt are block-and-wait.
– Beeno Tung
Jun 17 '19 at 8:32
...
Explanation of JSONB introduced by PostgreSQL
...me operation at a json typed value)
When jsonb will be available with a stable release, there will be two major use cases, when you can easily select between them:
If you only work with the JSON representation in your application, PostgreSQL is only used to store & retrieve this representati...
Shortcuts in Objective-C to concatenate NSStrings
...ly as pleasant as just having a concatenation operator.
First, use an NSMutableString, which has an appendString method, removing some of the need for extra temp strings.
Second, use an NSArray to concatenate via the componentsJoinedByString method.
...
SHA512 vs. Blowfish and Bcrypt [closed]
...nd others. It's good, but flaws have been recognized that, while not exploitable now, have led to the the SHA-3 competition for new hash algorithms. Also, keep in mind that the study of hash algorithms is "newer" than that of ciphers, and cryptographers are still learning about them.
Even though bc...
Parsing JSON using Json.net
...rays and Objects. These correspond here to the datatypes ArrayList and Hashtable.
/// All numbers are parsed to doubles.
/// </summary>
using System;
using System.Collections;
using System.Globalization;
using System.Text;
public class JSON
{
public const int TOKEN_NONE = ...
SQL WITH clause example [duplicate]
...me assigned to the sub-query is treated as though it was an inline view or table. The SQL WITH clause is basically a drop-in replacement to the normal sub-query.
Syntax For The SQL WITH Clause
The following is the syntax of the SQL WITH clause when using a single sub-query alias.
WITH <alias_n...