Skip to main content

LINQ for dummies - an overview


Why do we need LINQ?

Most of us would have wrote code to access data from different data sources a database, in memory objects , XML files or from other formats. We have different guidelines, architectures and methods to process and retrieve these data collection. For a data control in form it is immaterial whether the data is from XML or any other data sources. We have many relational OO databases but there always the gap between the data and its processing in Objects in any modern languages.


Is LINQ the Holy Grail?
I can’t decide on that. But LINQ tries to fill the vacuum between the datasources and their successful interpretation in Objects. With LINQ, Microsoft’s intention was to provide a solution for the problem of object-relational mapping, as well as to simplify the interaction between objects and data sources. LINQ eventually evolved into a general-purpose language-integrated querying toolset. This toolset can be used to access data coming from in-memory objects (LINQ to Objects), databases (LINQ to SQL), XML
documents (LINQ to XML), a file-system, or any other source.

LINQ can be used to access any type of object or datasource. The syntax remains the same. Previously we had to use different methods like ADO.Net.  XPath, IO packages etc to retrieve data ( ok still we can use these methods and in many cases I still prefer them over LINQ)

Broadly classifying we have three major categories of LINQ
  1. LINQ to Objects,
  2. LINQ to SQL,
  3. LINQ to XML

Don’t worry there are other categories like LINQ to datasets. LINQ to Entities ( with ADO.net entity framework). In Visual Studio you can write LINQ queries in Visual Basic or C# with SQL Server databases, XML documents, ADO.NET Datasets, and any collection of objects that supports IEnumerable or the generic IEnumerable(T) interface. In short .NET Language-Integrated Query defines a set of general purpose standard query operators that allow traversal, filter, and projection operations to be expressed in a direct yet declarative way in any .NET-based programming language. Third parties are also free to replace the standard query operators with their own implementations that provide additional services such as remote evaluation, query translation, optimization, and so on. By adhering to the conventions of the LINQ pattern, such implementations enjoy the same language integration and tool support as the standard query operators.

Next – LINQ in action ... 

Comments

Popular posts from this blog

SCRUM- Who should write a user story

Traditionally user stories (or requirements) were written by Business analysts. They used to prepare big documents after months of study. It was a herculean task. I used to get such UI/Functional specification documents. I have fixed a lot of bugs because I missed few text in such 1000 + pages document. This is not the only interesting part. Some of the requirements were so weird that I often wondered why I am creating the features which no one is going to use. If I had the option I would have recommended a better option. If the BA’s misunderstood some requirements & customers failed to correct those few words in the epic requirement then we will have a nice situation. In the agile world the story is different. Product Owners are primarily responsible for user stories. But can anyone else also contribute? Yes. Definitely yes In actual environment many users write user stories. The first requirement may come from end user. The PO, tech architect, scrum master, BA’s... anyone can up

What are the rules of scrum?

A relatively new person to scrum asked me this question last day. My answer to that person was yes. But really does the scrum have any rules? Scrum is a framework which helps us in developing software. It has very few rules and apart from those basic rules rest of them are guidelines like best practices. Some of the rules  The roles of Scrum • Scrum Master -  http://www.theagileschool.com/2012/03/scrummasters-checklist-roles.html • Product Owner • Feature Team The PDCA cycle ( http://www.theagileschool.com/2012/05/pdca-scrum-or-agile-why-is-it-important.html  )  frequent communication about risks (daily) • Plan – Sprint planning • Do – Actual engineering sprint – deliver a potential shippable code • Check – Sprint review • Act – Retrospective  The scrum guide @ http://www.scrum.org/Scrum-Guides will be a good guideline for teams/companies planning to start scrum. If you are following the recommendation in these then you are following scrum. Apart from these rest of

Product Backlog: Should you write everything in user story format?

I like user stories a lot. They help everyone talk the same language and results in a better product. User story alone does not constitute product requirement. User story is supposed to be a place holder for discussion which should happen between the team, Product Owner and the customer. This discussion result in a common understanding which along with the user story content is the product requirement. This format captures the essence of requirement without confusing the readers User Story is only one of the many different ways in which requirements can be represented. This is not mandatory in any Agile “process”. But many have made this mandatory. I have seen many spending countless hours trying to write the requirements in user story format when they could have easily written that in simple one-line sentence in few minutes.   I have seen team members refusing to even discuss the requirement until product owner rewrote the requirement in user story format. Once I