Ø the first choice is of course the objectspaces! that the. NET Framework will formally launch
Ø If you want total Solution,borland eco to be the best choice!
Ø Other
N Open source project recommended use OPF (foreign)
N Commercial Products recommended use Grove (domestic)
U design your own persistence layer
Ø If you want to design your own wheels, then the best reference is this article: Http://www.ambysoft.com/persistenceLayer.pdf
Ø Shanzhi, can attack jade
Here it mountain, non-Java, classic case hibernate already household name, you still need to wait?
Although the platform is different, but the outstanding design is everybody common wealth,. NET Guys hurry up and act!
Ø code is forever teacher, please pay more attention to these two. NET Open source projects:
N OPF
N ojb.net
Summary of L
U Data Access Layer the location of the entire system architecture
This is the last sketch of this article, and I hope to bring you some help:
U DAF Solution's Choice
Ø determine the interface is the key: No. 1!
Whatever technology is used, this is always the most crucial step: at least, the author thinks so.
After the adoption of DAF solution, in fact, the specific use of what data access logic technology is not necessary special care, as long as the interface to determine, even a lot of historical problems can be easily resolved!
Ø Access Technology arbitrary: Just do it!
General to do at present, when we design data Access logic, most need to decide in advance what technical framework, such as: Stored Procedure + dataset/datatable/dataview (Duwamish mode, simple structure, Easy to operate), or SQL + Provider Factory + DataReader + Entity (petshop mode, good performance, portable capability), and after the DAF solution, these are no longer obstacles to the system architect for data Access Logic Design-time hurdles!
You can do this: all design time takes the Duwamish mode, while the partial data Access logic operations are adjusted to PetShop mode when implemented (possibly based on performance considerations). Even if other layer callers are not particularly familiar with ado.net (normal), you can also decide to use O/R Mapping within some of the data Access logic, which can be easily followed by OO after the entity façade return!
Still, however, some issues require specific analysis:
(1) Stored procedure bring convenience and high performance, but also have transplant problems to consider;
(2) O/R mapping in improving ease of use, but also for performance, complexity paid a certain price;
(3) When the use of DataReader, how to access the dataset, is always an intractable problem (although the author has made assertions about this), love and hate dilemma!
(4) is the use of distributed Process? How to solve the security problem? NET Remoting does not offer a good solution, but does webservices guarantee compatibility with other systems?
Just 4 cases, this shows.
Although these practical problems have to be solved, but in daf this tree, you still have greater freedom, no longer for the unified architecture design and frequently add a lot of trouble!
Østorage: Data Entity facade!
Here, the author thinks, perhaps it is more appropriate to call it "persistence."
It can be said that the DAL's cornerstone is from DAF, and DAF and the outside bridge is the data Entity Façade. It is their unified appearance that allows us to be free to cope with all the changes that may occur at any time!
return XML? No problem!
Do you want to change the calling code after returning XML? It's simple, be a entityconvert!.
O/R mapping cool, let me go back to the object? Change the configuration file, and then write a
O/R Mapping Data Access logic! Isn't that cool, too?
The dataset has overwhelmed our systems and customers have recently complained frequently about: you call the
The webpage has not answered for a while, please brush later, how to do?
This is not difficult: take down the dataset and replace it with Datareader,data Entity.
Façade has built different data access base stations onto your server, which
will ensure that your system 99.98% is in the service area (and 0.01% may be your
Forget to play the latest patch of the. NET framework, and the remaining 0.01% is fine.
Do, go and buy a new memory or add a CPU bar!
...... (If you need to return to other systems can not recognize the east, please call the following toll-free: 800820XXXX,DAF solution team will help you ... ）
The true meaning of n in the framework of U N-tier
Very simple, 2 words end:
n==? Not important, the key is: Data access Layer!
To structure well, the interface is the lifeblood!
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