I am pretty much sure that you are aware of indexes which we are creating on database fields. Indexes are very useful to make your query search faster and improve the site performance. But the fact is that Indexes which we are creating on database tables also require some additional space on your hard disk and if you have not properly created these indexes than some times your index size become more than your actual data size.Now what if you can compress indexes which you have ...

There are times where running IF statements inside a query can be useful. MySQL provides a simple way to do this through the use of IF and CASE statements.The IF statement takes three arguments; the conditional, the true value and the false value. False and true values may be static values or column values. For example:SELECT IF(score > 100, 100, score) AS scoreFROM exam_resultsthis will return the value in the score column limited to a maximum value of 100. IF statements can also be nested:SELECT IF(score > 100, 100, IF(score < 0, 0, score))FROM exam_resultsCASE statements (s...

Oracle CEO Mark Hurd had an interview with Chinese media in San Francisco on 19th April. Mark Hurd first introduced different levels of Oracle's overall strategy: 1) the product must achieve best among similar products; 2) system open, vertical integration to provide customers with maximum performance; 3) Industry specific solutions; 4) give users the right to choose and the integration of the cloud environment (private cloud, public cloud, mixed cloud). In addition, Mark Hurd share his own views about a few hot topics.1. Acquisition strategy: an important supplement to R & D / product sy...

IntroductionBefore you start reading this article let me confirm that I am not a guru in database designing. The below 11 points which are listed are points which I have learnt via projects, my own experiences and my own reading. I personally think it has helped me a lot when it comes to DB designing. Any criticism welcome.The reason why I am writing a full blown article is, when developers sit for designing a database they tend to follow the three normal forms like a silver bullet. They tend to think normalization is the only way of designing. Due this mind set they sometimes hit road blocks ...

Updated 2011-11-28: Added reference to the walkthrough of using LocalDB in Visual Studio 2010 and to the new LocalDB Installer.Updated 2011-11-02: Added reference to .NET Framework 4 support for LocalDB in the Q&A section.IntroductionIt gives me great pleasure to introduce a new version of SQL Express called SQL Express LocalDB.LocalDB is created specifically for developers. It is very easy to install and requires no management, yet it offers the same T-SQL language, programming surface and client-side providers as the regular SQL Server Express. In effect the developers that target SQL Se...

Use well defined and consistent names for tables and columns (e.g. School, StudentCourse, CourseID ...).Use singular for table names (i.e. use StudentCourse instead of StudentCourses). Table represents a collection of entities, there is no need for plural names.Don’t use spaces for table names. Otherwise you will have to use ‘{‘, ‘[‘, ‘“’ etc. characters to define tables (i.e. for accesing table Student Course you'll write “Student Course”. StudentCourse is much better).Don’t use unnecessary prefixes or suffixes for table nam...

I have been playing around with Hybrid Word Aligned Bitmaps for a few weeks now, and they turn out to be a rather remarkable data structure.  I believe that they are utilized extensively in modern column oriented databases such as Vertica and MonetDB.Essentially HWABs are a data structure that allows you to represent a sparse bitmap (series of 0's and 1's) really efficiently in memory.  The key trick here is the use of run length encoding to compress the bitmap into fewer bits while still allowing for lightening fast operations.  They key operation from my perspective ...

In modern web development, it’s standard practice to make use of a database abstraction layer, typically an Object-Relational Mapper based on either the Active Record pattern or the Data Mapper pattern. There are several pros and cons to this which are fairly well established, so I’ll spare us all from enumerating them all right now.One established pro worth mentioning is that these systems typically provide a high level interface for fetching data, often removing the need to ‘hand write’ SQL for anything but the most complex of query.As good as this sounds it h...