Prior to the release of the Microsoft .NET Framework, programmers had few data access technology choices for interacting with data stored in a database. An ActiveX Data Object (ADO) Recordset was the option commonly used to hold query results and data contents. It originally required a constant database connection to maintain access to the data. Over time it was evolved to support disconnected applications as well as provide some limited support for eXtensible Markup Language (XML).
The release of ADO.NET offers a new object model for retrieving data. Now there are two data classes for query results and a slew of other classes to hold various data content. Since most programmers are used to only having a single Recordset, this raises the questions of why there are two data retrieval classes in Microsoft .NET and which is the best to use.
What is a DataReader?
A DataReader is a read-only stream of data returned from the database as the query executes. It only contains one row of data in memory at a time and is restricted to navigating forward only in the results one record at a time. The DataReader does support access to multiple result sets, but only one at a time and in the order retrieved. Just as in the original version of ADO, the data is no longer available through the DataReader once the connection to the data source is closed, which means a DataReader requires a connection to the database throughout its usage. Output parameters or return values are only available through the DataReader once the connection is closed.
May 2, 2011
Top 10 Firefox Add-Ons for Web Designers
There are plenty of Firefox add-ons at your disposal that can extend the browser’s core functionality. The types of add-ons you’ll encounter have a wide range of utility, from productivity tools that monitor the amount of time you spend on the Internet, to social media tools that conveniently give you in-browser capabilities for using popular services such as Twitter and Facebook.
The Firefox browser is a popular choice for web designers, and there are plenty of add-ons that can make the day-to-day work of web design significantly more efficient and fruitful. Here are 10 highly recommended, top-notch Firefox add-ons for web designers. Let us know what other Firefox add-ons you use in the comments.
1. Web Developer
The Web Developer Firefox add-on is a huge suite of web design tools packed with massively useful functions that will help web designers perform tasks more efficiently. By default, it displays as a toolbar towards the top of the browser, presenting you with various menus such as CSS, Resize and Cookies.
Whether you need to inspect the CSS of page, discover information about a webpage (such as seeing all the alt attributes of images on the page), quickly validate a web design for W3C compliance or measure design elements, Web Developer will likely have a convenient tool for you.
2. Firebug
Firebug is such a popular web design/front-end web development Firefox add-on that there are actually add-ons for it (see no. 5). And if you were to ask any web designer or web developer what Firefox add-on they can’t live without, chances are he’ll say Firebug.
Firebug is an open source add-on that gives web designers powerful tools for inspecting and debugging a web design. It can help you figure out what CSS styles affect certain elements (in case you’re having trouble with a style rule that doesn’t seem to render properly), inspect the document object model (DOM) to learn about the structure of the web page, determine attributes such as color, width, height of HTML elements and much more.
The extension can take a while to learn (trust me, it’s worth the time), but the creators have some helpful documentation to get you started.
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