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When rendering a form 'by hand', it can be useful to know if there are fields left to render or not. The function isRendered() from the FormView class returns true if there are still fields left to be rendered to the template. This snippet prints <h3>Extra fields</h3> if there are fiel...

Group Concat is used in MySQL to get concatenated values of expressions with more than one result per column. Meaning, there are many rows to be selected back for one column such as Name(1):Score(*) NameScoreAdamA+AdamA-AdamBAdamC+BillD-JohnA- SELECT Name, GROUP_CONCAT(Score ORDER BY Score desc SE...

CREATE TABLE foo ( ... name CHARACTER SET utf8mb4 ... );

There are dozens of character sets with hundreds of collations. (A given collation belongs to only one character set.) See the output of SHOW COLLATION;. There are usually only 4 CHARACTER SETs that matter: ascii -- basic 7-bit codes. latin1 -- ascii, plus most characters needed for Western Eur...

Getting zsh zsh is available on many UNIX-like platforms via their built-in package management systems. On the Debian and Ubuntu Linux distributions, zsh is available in the default package repositories and can be installed using: $ sudo apt-get install zsh # or, on newer Ubuntu distributions $ ...

Pattern synonyms are abstractions of patterns similar to how functions are abstractions of expressions. For this example, let's look at the interface Data.Sequence exposes, and let's see how it can be improved with pattern synonyms. The Seq type is a data type that, internally, uses a complicated r...

A real world example using a scientific experiment where certain routines are performed on different types of tissue. The class contains two functions by default to get the tissue or routine separately. In a later version we have then adapted it using a new class to add a function that gets both. Th...

Visitor pattern allows you to add new operations or methods to a set of classes without modifying the structure of those classes. This pattern is especially useful when you want to centralise a particular operation on an object without extending the object Or without modifying the object. UML diag...

The yield keyword allows lazy-evaluation of the collection. Forcibly loading the whole collection into memory is called eager evaluation. The following code shows this: IEnumerable<int> myMethod() { for(int i=0; i <= 8675309; i++) { yield return i; } } ... // ...

Consider using Extension Methods as Functions which wrap other code, here's a great example that uses both a static method and and extension method to wrap the Try Catch construct. Make your code Bullet Proof... using System; using System.Diagnostics; namespace Samples { /// <summary&g...

Many database configurations require authentication (in the form of a username and password) before you can query the database. You can supply these using the username and password attributes. Note: the username and password can also be configured against the datasource in the ColdFusion Administra...

Consider the following struct definitions: struct Foo { my_bool: bool, my_num: isize, my_string: String, } struct Bar (bool, isize, String); struct Baz; Constructing new structure values for these types is straightforward: let foo = Foo { my_bool: true, my_num: 42, my_string: ...

C.I.A.s are intended as a simple way of getting attributes from whatever is calling the targeted method. There is really only 1 way to use them and there are only 3 attributes. Example: //This is the "calling method": the method that is calling the target method public void doProcess() ...

using System.ComponentModel.DataAnnotations; public class Post { public int Id { get; set; } [StringLength(100)] public string Title { get; set;} [StringLength(300)] public string Abstract { get; set; } public string Description { get; set; } } Def...

[TimeStamp] attribute can be applied to only one byte array property in a given Entity class. Entity Framework will create a non-nullable timestamp column in the database table for that property. Entity Framework will automatically use this TimeStamp column in concurrency check. using System.Compon...

Android Studio's Live templates can offer quite a few shortcuts for quick logging. To use Live templates, all you need to do is to start typing the template name, and hit TAB or enter to insert the statement. Examples: logi → turns into → android.util.Log.i(TAG, "$METHOD_NAME$: $content$&q...

What's between \Q and \E is treated as normal characters #!/usr/bin/perl my $str = "hello.it's.me"; my @test = ( "hello.it's.me", "hello/it's!me", ); sub ismatched($) { $_[0] ? "MATCHED!" : "DID NOT MATCH!" } my @match = ( ...

It can be difficult to test functions with poor asymptotic complexity using quickcheck as the random inputs are not usually size bounded. By adding an upper bound on the size of the input we can still test these expensive functions. import Data.List(permutations) import Test.QuickCheck longRunn...

el-get is an open source package management system for GNU Emacs. el-get works with melpa, as well as with many common version control systms. Its documentation includes a simple self-installer for your .emacs: (unless (require 'el-get nil t) (url-retrieve "https://raw.github.com/dim...

This attribute is applied to the class property. You can use ConcurrencyCheck attribute when you want to use existing columns for concurrency check and not a separate timestamp column for concurrency. using System.ComponentModel.DataAnnotations; public class Author { public int AuthorId { ...