Sure ActiveX but what is COM+?

[Hawk]

Hi,

I understand the nature of ActiveX Dll and ActiveX Exe. How remote COM and DCOM is used. I have a question that is related to this material. What is the purpose of using COM+ or MTS? I read roughly that it has to do something with transaction but what is the over all concept behind it? I really like to understand this.

Thanks

Hawk

[Edneeis]

As far as I understand COM+ is basically like COM version 2. It is just an improved version of COM.

MTS is for COM datasources (sort of) the main benefits are connection pooling and things of that nature but I'm not too familiar with it really so I'll leave the rest for someone else.

[deja]

(sorry, my english is not very well)
ever heard about DNA?
DNA is m$ solution for bulding distributed application (DNA stands for Distributed interNet Application).
when building distributed systems few things must be considered.
application can be distribute across wide area such as WAN.
data can be stored in separate location and on different platform.
user interface can be web style or windows style.
application can be accessed by thousand of users.
security must be implement.
develop process must be easy as possible and so the maintaining.
application must be robustness, available, and easy to scale.

to fulfillment those challenges, microsoft bases heavily on COM.
DNA uses the concept of tiers (or N-tiers) by separating user interface, bussiness logic and data services.
user interface can be web based using technology such as ASP, DHTML, ActiveX etc or windows based using win32 infrastructure.
bussiness services can be built using COM+ and RAD tools such as VB.
data source can be stored in SQL server or other providers.
application can take advantage of other m$ technologies such as IIS, DCOM, ADO, MSMQ and more.
separating application into tiers gives u more flexibility and scalability.
u can have number of different user interface that targeting the same bussiness services (no need to replicate DLL's for each UI).
modifying bussines logic need only in one place.
can easily add access to other data sources (also for legacy systems) without interrupting the user.
u can put all SQL statements in stored procedures by that u:
* don't transferring SQL on the net.
* take advantage of the DBMS features, such as programming language, compiled SQL, LRU statements already in memory.
* take advantage of OLE DB connection pooling.

i'll stop here talking about DNA and focusing COM+ (u can read more at MSDN).
COM+ is runtime environment for COM objects in the middle tier business logic.
COM+ replacing MTS and enhance it.
COM+ provide services such as Transaction, Load Balancing, Queued Components, Events, Security, JIT Activation and lot more.
COM+ transactions can participating and accessing many data source like Oracle, DB2 etc.
if u had to implement distributed transaction by your self it would be very difficult.
COM+ uses DTC to managing transaction against range of DBMS.

read more about COM+ at MSDN:
http://msdn.microsoft.com/library/de...asp?frame=true

[Hawk]

Deja, that is alot of information to digest but I have to read it again.