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Dynamic Query Engine: When I read the article
ADO.NET v2.0: ObjectSpaces Delivers an O/R Mapper I
also got a confidence that Microsoft is also going in
similar directions. The hardest change for me to grasp
was that LLBLGen Pro uses a dynamic query engine that
generates queries on the fly allowing high level object
oriented commands to replace stored procedures. As one
that uses SPs exclusively this made me very nervous.
After reading many threads about how the Java has been
doing this for years, and that there is a move away from
SPs in process for many reasons including performance
comparisons merging with the ability to support many
databases. Consider the case were a table has many
fields of interest. You want to filter on any
combination of these each trip to the data. In this new
world you do not have to write many SPs, but simply
instantiate a Sort and Filter object and use them in a
dynamic query. Because of this the LLBLGen Pro can now
support SQL Server, and Oracle versions and has more
databases planned for near future. LLBLGen Pro can be
applied to a project with SPs in stream since it will
support the SPs that currently exist.
Entity classes and Typed lists: In the open
source version there was one class generated for each
table and if you looked at the code it made immediate
sense. In the Pro version, each table gets base class,
derived class, data class, validation class, etc
depending on the generation configuration you choose.
The code in these classes is not immediately obvious,
but the interface is simple. Validation classes are
separate so they never need to be regenerated and you do
not lose your customizations to the validations. Typed
lists are basically readonly lists coming back as
strongly typed datatables selected from related
tables within the gui form. When you need to add a
field to a database table you will regenerate that
class, but only the base class will be changed. Since
your custom methods and properties are in a derived class
or sub class of the base you never lose any code due to
regeneration.
Collection Class support: If you want to work
with a class directly (not in context of a parent
class), you get a strongly typed datatable. If there is
a relation between customer and order in your database,
then when you want a customer 1 to many order screen
with only the orders for customer 9330, you execute the
following 3 lines of code where 9330 is the primary key
id:
Dim customer as CustomerEntity(9330)
orderGrid.datasource = customer.orders
orderGrid.databind
Further lazy loading capabilities allow you to load
customer object instance without loading all orders for
that customer, and all detail order lines for each
order, and all shipping addresses for each order, etc.
Then as soon as you access the customer.orders.details
the details fill in for the orders if they are not
already loaded from the database. Further, a partially
dirty/changed collection of details of an order can be
sent with one method in batch mode back to the database
for one shared repository update so other threads see
all the pertinent changes at once. The classes know
whether an insert or update is the proper thing to do so
you can just do customer.save() Further, if I have
a reference to an Order, I can get a reference to the
customer of that order by simply referencing
order.customer.
Binding Support: Classes will truly bind to
web/windows forms due to change events built in to the
entity classes.
Transaction Support: If no manually created
transaction is presented, one is wrapped around your
class.
Extension Support: An SDK is currently
available to customers for changing the features of the
program.
Deployment Support: When you generate, there
is a .NET project file created that made it easy for me
to add this project to any solution. Then I added a
reference to that project from my main project, added
imports statements on each page for the main areas and
was off an running using the classes. (watch out for
field names in tables that are VB keywords since that
won't be handled automatically by the generator) |
