Hey! how is the microsoft way of 3-tier architecture? see this link: http://sdn.microsoft.com/library/default.asp?url=/library/en-us/dnbda/html/BOAGag.asp how is this article? and what's the best way to map Relational Data to Business Entities? i think you
need to create entities that represent the data.. but each entity is one object or one 'datarow', what to do if you want to get a complete list of (selected) rows from the database? create a ilist of the entities? and is better to make an entity for each table?
or to merge related data in one class? Thanx, Tarek PS: it still diffecult to chose the way for passing data: - Passing Scalar Values As Inputs and Outputs - Passing XML Strings As Inputs and Outputs - Passing DataSets As Inputs and Outputs - Passing Custom
Business Entity Components As Inputs and Outputs - Returning Data Readers As Outputs does someone have a GOOD example of a 3-tier application ? (a complete one, on microsoft site you see each time a part or only one layer:S) that i can use as a refference?
Bluemagics Weblog: "I'll always make your dark sky blue!"
how about build your application then build your data model to persist your model's data :) rather than the reverse way of building the data model then building the objects ... you may find that the objects require things that your data model cannot handle
if you go data->application ...
An O/R mapper is more generally called a persistence layer. You give the persistence layer knowledge about your domain classes like the name of the data table where the class is persisted and the column name where each field is saved. With this knowledge, the
persistence layer can dynamically generate the sql statements to move data between objects in memory and relational tables in the database. That means you write a lot less code.
::an O/R-mapper generates the DAL? Only a bad one. There is actually never any need to GENERATE a DAL. An O/R mapper will normally include a generc dal that configures itself using schema information available (which is also possible without an O/R mapper -
I really wonder what people consider "good programming" in writing the repetiticve DAL code themselves). An O/R mapper basically means your BLL contains object, and you dont have to deal with anything below the objects (like persistence, SQL etc.). This is
actually THE way to write applications, and a great timesaver - it can reduce your code-count by about 30% upwards.
An O/R Mapper maps "automatically" your BO's to Tables. In other words, if an O/R mapper is used, potentially any object in a framework is a Custom Business Entity as defined by Microsoft. If a Data Model already exists there should be no problem, unless your
data model is of a data domain totally different then the domain represented by the object model. The benefit of it, is that you don't have too worry about all the technical details that the whitepaper described and focus on your business problem.
But if the use of O/R mapping is the way, why did't microsoft talk about it in its tutorials:S and why didn't microsoft include an O/R-mapper in visual studio? *usualy microsoft includes everything in there products for 'free' *okey okey... not 100% free, it's
a (nice) weapon against the rest* I need a second opinion: which O/R mapper is the best ? (6) grtz, Tarek
Bluemagics Weblog: "I'll always make your dark sky blue!"
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