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...

Look, everyone makes mistakes. It’s true. But not all of us have the chance to make mistakes that end up costing millions of dollars in hardware and production support costs.Any one of the following five mistakes listed below will add additional costs to your company. It’s guaranteed. The costs could be hardware related (extra disk space, network bandwidth), which tend to add up quickly. The costs are also support related (bad performance, database re-design, report creation, etc.), and they add up very quickly.Want to save your company some money, some headaches for yo...

The difference is subtle, but it is a big difference. The ON condition stipulates which rows will be returned in the join, while the WHERE condition acts as a filter on the rows that actually were returned.Simple example: Consider a student table, consisting of one row per student, with student id and student name. In a second table, a list of grades that students have received, with student_id, subject, and grade. Give me a list of all students, and show their grade in Math. This requires a LEFT OUTER JOIN, because you want all students, and you know that some of them didn't take Math. Here a...

New features are added with every release of SQL Server and as a result, some features get removed or deprecated. Deprecated features are features that are still operational (for backward compatibility) but will be removed in a future version. Deprecated features can be of two types: those that will be deprecated in a future version and those that will be deprecated in the next version.In this article, we will explore how to track deprecated code and correct it. I will also share our observations when we performed the same operation on a live production database. Please feel free to ...