developer-express

jQuery: Find the label text for a selected radio button

2011-03-04T02:15:00.001-08:00

Sometimes the seemingly easiest pieces of code can end up giving you trouble. This morning I was working on a project where I wanted to display the text (not the value) of a selected radio button.

In the end it was very simple. I added a label to my radio buttons and used the following line of code.

$('input[name=myname]:checked + label').text();

SQL Concatenation with the STUFF function and XML PATH clause

2011-02-22T07:30:00.001-08:00

Recently I had the necessity to retrieve a concatenated string of values as a column for a report. This can be achieved quite simply by creating a UDF that returns the concatenated string and calling within the SELECT statement.

However, I do not like using UDF’s within SELECT statements due to performance issues. So I started searching the net for a possible alternative and came across the following:

http://www.kodyaz.com/articles/concatenate-using-xml-path.aspx

Now I have never used the SQL STUFF function or XML Path clause but the combination of the two enabled me to achieve my goal very quickly.

The STUFF function inserts a string into another string. It deletes a specified length of characters in the first string at the start position and then inserts the second string into the first string at the start position.

You can execute SQL queries to return results as XML instead of standard rowsets. These queries can be executed directly or executed from within stored procedures and user-defined functions. To retrieve the results directly, first use the FOR XML clause of the SELECT statement.

SELECT TOP 1
STUFF(
            (
                SELECT ', ' + Username
                FROM Users
                FOR XML PATH('')
            ), 1, 1, ''
        ) As ListOfUsers
From Users

An Introduction to Using Patterns in Web Design

2011-02-15T06:32:00.001-08:00

A fantastic article from Ryan Singer at 37 Signals.

http://37signals.com/papers/introtopatterns/index

The use of design patterns in web design can help developers tackle the tricky balance between user experience and business objectives.

SQL: OVER Clause

2011-02-04T07:37:00.001-08:00

The OVER clause allows partitioning and ordering of the rowset.

The syntax for this function:

Ranking Window Functions

< OVER_CLAUSE > :: =

OVER ( [ PARTITION BY value_expression, ... [ n ] ]

<ORDER BY_Clause> )Aggregate Window Functions

< OVER_CLAUSE > :: =

OVER ( [ PARTITION BY value_expression, ... [ n ] ] )

As specified above the OVER clause can be used in conjunction with aggregate functions, which can make your code a little shorter.

For example, consider the following bookings table:

SELECT * FROM #Bookings ORDER BY CourseID

CourseID	DelegateID	BookingDate	BookingCost
1	1	2011-02-04	10.00
1	2	2011-02-04	10.00
2	1	2011-01-04	10.00
3	1	2011-03-04	50.00
3	2	2011-03-04	50.00

Now it is quite simple to return the total cost per delegate by using the SUM aggregate function with the OVER clause.

SELECT CourseID, DelegateID, BookingDate, BookingCost, SUM(BookingCost) OVER (PARTITION BY DelegateID) AS TotalCost FROM #Bookings

CourseID	DelegateID	BookingDate	BookingCost	TotalCost
1	1	2011-02-04	10.00	70.00
2	1	2011-01-04	10.00	70.00
3	1	2011-03-04	50.00	70.00
1	2	2011-02-04	10.00	60.00
3	2	2011-03-04	50.00	60.00

An alternative SQL sctipt without using the OVER clause would be:

SELECT CourseID, DelegateID, BookingDate, BookingCost,
(SELECT SUM(BookingCost) FROM #Bookings BK WHERE BK.DelegateID = #Bookings.DelegateID) AS TotalCost
FROM #Bookings

jQuery 1.5 Released

2011-02-01T14:18:00.000-08:00

jQuery 1.5 was released for consumption today!

Grab jQuery 1.5 here

This release includes:

Complete rewrite of the Ajax module.
New feature: Deferred Objects
New method: jQuery.sub()
Performance improvements (Adjacent Traversal)
Bug Fixes - Approx 83

Responsive Web Design

2011-01-22T08:36:00.000-08:00

For me, Responsive Web Design is a relatively new term. Basically it refers to a web design layout that alters to it's environment. So the layout can alter depending on the screen size or resolution. This is not the same as a fluid design though, with Responsive Design the lay can actually change rather than just scale down.

A List Apart has a fantastic article on Response Web Design

I really like the idea of Responsive Web Design but it does seem a lot of effort, so I intent to start messing around with some CSS frameworks that embrace it.

Free eBook for Web Designers: 5 Tips for Better Sites

2011-01-22T08:16:00.000-08:00

Webvantas 5 tips for better sites:

1. Draw the line between design and implementation
2. Think in terms of information architecture
3. Pick the best CMS for your needs
4. Know What jQuery Can Do for You
5. Drive traffic with SEO and social media

Free eBook for Web Designers: 5 Tips for Better Sites

A good set of guidlines which may seem obvious but are often overlooked, especially once development has begun. Many times development projects go astray because developers "cannot see the wood for the trees". I participially like tip 3 but would not limit it to the CMS, choose the right tool for job period.

SQL: Format Dates with DATENAME()

2011-01-21T01:00:00.000-08:00

DATNAME() is an ANSI compliant, fast date part function built into SQL Server.

It accepts two arguments datepart and date. The datepart parameter specifies which part of the date to return - day, month, year with the function returning an nvarchar.

Syntax

DATENAME ( datepart ,date)

Example

SELECT DATENAME(m, GETDATE())

Result

January

http://msdn.microsoft.com/en-us/library/ms174395(v=sql.90).aspx

Capitalise first letters in SQL Server

2011-01-20T04:46:00.000-08:00

SQL Server has no built in function to capitalise the first letter of each word in a string. The function outlined below will do just that.

This function has proved very valuable!

Source: http://www.sql-server-helper.com/functions/initcap.aspx

Partial Classes, Interfaces & Generics

2010-11-04T02:28:00.000-07:00

Partial classes can be used to split definitions of classes, structs or interfaces over two or more source files. Each source file contains a section of the class definition which are combined at when the application is compiled.

Partial classes can be beneficial in the following situations:

Working on large projects, allowing developers to work on different sections of a class without both having to access the same physical file.

Working with generated source code, as code can be added to a class without touching the original source file.

Improve maintainability by logically grouping code.

An interface is a contract between classes. An interface is particularly powerful in C# as it allows multiple inheritance.

Interfaces are abstract types that contain no actual data but simply expose behaviours to the classes that implements them.

Generics use type parameters, which allow classes and methods that can defer specification until they are instantiated.

Maximises code reuse, type safety and performance.
Most common use in collections

C# System Types

2010-10-29T08:12:00.000-07:00

The type system in .NET or Common Type System (CTS) divides types into 2 categories:

Values Types
Reference Types

Value Types

These are simple data types that directly contain their data, for example:

Integers
Floats
Enums
Structs

Reference Types

These types store references to objects. Reference type variables have the ability to refer to the same data, so two variables can point to same object and the object be manipulated by performing operations of both variables. Examples include:

Classes
Interfaces
Delegates
Arrays

SQL: Format Dates

2010-10-28T01:05:00.000-07:00

Formatting dates in T-SQL is generally a nuisance as no format date function exists. In the past I have seen many developers (including myself) use the DATEPART() functions to split the dates and then manually build up a date string.

Alternatively I have seen developers CAST() the date to format.

Recently however, I discovered the different date formats that come standard in SQL Server as part of the CONVERT() function.

For an excellent thorough list of date formats please visit http://www.sql-server-helper.com/tips/date-formats.aspx

SQL: Get the length of text, ntext & image

2010-10-27T05:04:00.000-07:00

Ever needed to find the lengh of a ntext field in SQL only to be met with the following error message, whilst using the LEN() function?

This can be achieved by simply using the DATALENGHT() function. DATALENGTH is especially useful with varchar, varbinary, text, image, nvarchar, and ntext data types because these data types can store variable-length data.

Note: Compatibility levels can affect return values. For more information about compatibility levels

Getting Started with LINQ to Entities

2010-09-29T12:39:00.000-07:00

Introducing the object context, basics queries, eager loading, lazy loading and projection.

In this video, Julie Lerman will show you how to query your database with LINQ to Entities queries against an Entity Data Model. This video uses Entity Framework 4.0 and Visual Studio 2010.

Presented by Julie Lerman.

Context object
var context = new myModel.MyEntities

Basic query
var query = from c in context.Customers select c;
var customers = query.ToList();

Basic filter query
var query = from c in context.Customers where c.customerID==5 select c;
var customer = query.FirstOrDefault();

Eager loading
var query = from c in context.Customers.Include("SalesOrdersHeaders") where c.customerID==5 select c;
var customer = query.FirstOrDefault();

Lazy loading (.NET 4 only)
var query = from c in context.Customers where c.customerID==5 select c;
var customer = query.FirstOrDefault();
lblTest.Text = customer.SalesOrdersHeader.Count

Projection
var query = from c in context.Customers where c.customerID==5
select new { c.CustomerID, c.Firstname, c.Lastname };

Creating an Entity Data Model from a Database

2010-09-21T11:20:00.000-07:00

The entity framework is an object-relational mapping (ORM) framework for the .NET Framework. The entity framework separates the conceptual and logical data models, allowing developers to program against the conceptual model rather than the logical model.

This video walks you through the basics of creating an entity data model from an existing database using Entity Framework 4.0 and Visual Studio 2010. You’ll learn to run the Entity Data Model wizard, connect to a database, and select database objects for your model. Once the model has been created, you’ll then learn about the basic features of the model such as the entities, associations and properties.

Presented by Julie Lerman.

JSON - An Express Overview

2010-08-07T04:14:00.000-07:00

Whilst building a new reporting engine this week I was advised by a friend to consider using JSON as a simple and effective way to store the business rules. Having not used JSON before, I decided to take a quick look and found it to be a very straightforward yet elegant way of storing data.

What is JSON?

JSON (JavaScript Object Notation) is a neat and structured text-based data format that is an accepted alternative to XML.

JSON comprises of two structures:

A set of name/values pairs, which is basically an object. Both the name and value mus be in double quotes.
An ordered list of values, which is basically an array. Values in turn can store strings, numbers, objects, arrays, Booleans and nulls.

Basic Objects

var jString = { "Firstname": "Joe", "Lastname": "Bloggs" }

document.writeln(jString.Firstname); // Output Joe

Basic Array

var jString = { "Firstname": "Joe", "Lastname": "Bloggs", "Sports": ["Football", "Tennis", "Jujitsu"] }

for (var i in jString.Sports) {
document.writeln(jString.Sports[i]);
}

// Ouput: Football Tennis Jujitsu