Sharepoint BDC - Easy LOB Integration

BDC
MOSS 2007 brings out new capabilities in integrating third party data sources and line-of-business apps into the sharepoint environment. Once integrated, these data sources act 'quite' similar to the standard sources letting you apply the various sharepoint functions such as list, search etc.

There is no need to write complex custom handlers (nobody wants to write one - not recommended by the MOSS team either!) or IFilers, now with the introduction of Business Data Catalog - BDC

The idea is very simple - you could integrate any data source which has an adapter via the ADO.NET path or a webservice. Once you dig out the adapter,the only remaining step is to define the BDC. The BDC definition is an XML file conforming to the BDCMetaData.xsd schema. Tip - when you start with a new XML file using VS.NET 2005, go to the properties for this XML file and point the 'schema' to the BDCMetaData.xsd; this enables intellisense while editing the XML file.

Common items which you define in the BDC :
LobSystemInstance - This defines where the datasource is and the adapter to use for connection, think of it as the connection string you normally provide.

Entities - When you expose the data source, what you definitely need to tell MOSS is what items you need to make available from your datasouce. Say from the default SQL Server [pubs] DB, you might want to expose the employee items only. For each entity, you would need to define the properties (employee id, name etc) and the identifier (employee id) at the bare minimum.

Methods and Method Instances - This defines the actions you could perform against the entity. You would define the method defintion ; say by using an SQL command string with the parameters (parameter types could be .NET types, say System.Data.IDataReader, System.String etc).

Method instances is an interesting concept; the same procedure definition (a template) could have different roles (method instances) to play under different scenario. Method types define the role the method plays. Eg:- when you need to define a SpecificFinder and a Finder type, a single method template should suffice.

Some of the method types defined are quite smart; AccessChecker method type could be used to do a custom access filter of the items in MOSS just before it is shown to the user (say just before the search result is shown within MOSS). You could write stored procedures in the backend which tell MOSS whether the data needs to be shown to the specific user, then link it up as an AccessChecker in the BDC definition file. I think thats cool.

BDCMetaMan - A very handy tool where you define the connection, entities etc visually and the XML file is generated for you. The free version could be used as a draft for more hands on tweaking.

Check out BDC covered extensively at MSDN.

Survival tips for the 'common programmer'

Learn Learn
For the 'common programmer'[R.K Laxman - 'Common Man' variant], the importance of a good foundation in computer science and continuously upgrading your knowledge cannot be emphasised further. The reason for this post are the many interviews conducted over the past few days which have been very disappointing and a few talks with my colleagues.

In addition to computer science fundamentals, what definitely appear to be missing from the many software professionals is the passion to learn stuff, the desire to look into the details to know how things works

Your basic foundation, which should have at least covered computer architecture, OS fundamentals, Networking fundamentals, programming concepts and constructs (for a more exhaustive list, check out the syllabus from any of the B.Tech or B.Sc Computer Science courses) seems to be missing.

Second, you need to be aware of whats around and happening in this field; now how would I do that ? Subscribe to postings via a good RSS reader - Google Reader is a good option. Nearly all websites support for RSS subscriptions. Most importantly, make sure you read through them periodically.

Information Overload ?
Now, while reading through the many stuff, how do you make sure its relevant to you ? There is no way anyone could read and understand each of the topic (that would take 25hrs daily... behind bars perhaps?). An easy option is to not go into the details of the implementation, but be aware of the concept; as in, know the fundas. Unless the posting itself is of an interesting nature and you want to go in deeper.

The same logic applies to newsgroup postings; subscribe to newsgroups which appear interesting, but be aware of what needs a closer read. The experts appear to 'read between the lines'; you could skip paragraphs and sentences to read through the article to get an overall idea. If it does appears interesting, go back and read all the lines.

Overall, just make sure you are updated - make the above two steps a habit :)

Look Further
Now, when you learn something new, make sure you delve a bit more deeper than the skin to understand the hows and whys. These two questions should clear a lot many doubts on why the stuff is there in the first place and how the stuff solves it.

eg:- Most of us appear to know that the foreach construct in C# lets you loop through each items in the collection (solves the 'why' part). All good. Now, how does it do it and how can I extend my System.Object descendant to be made usable within the foreach construct? Enter IEnumerable interface.

Another one - Threads in C# do let me run jobs in parallel ('why' part). Now how does the CLR manage user threads? Did you know that a thread need not be created at the OS level each time a /new Thread()/ is called ? Enter Thread pool managed by the CLR.

What needs to be stressed is the importance of going deeper into anything you learn by answering the above two questions each time.

All the best fellow programmers. Would like comments on how you guys learn and update yourself.