1. What is DAP
DAP (database access platform) is a
database persistence and query service for java.
Similar to O-R mapping product, it treat
the database tables as java object, and these objects take over all the
operation to the database, Such as query and persistence.
Features:
- platform: java 1.3.1 or above
- Using common data
type for all tables – DataSet
- Database type
enwrapped. User needn’t to write different code for different database.
Current it support database of ORACEL and DB2.
- Transaction type
enwrapped. User needn’t to write different code for local transaction and
distributed transaction.
- Operation
efficiency enwrapped. User needn’t to care about it since the SQL
statement can be generate automatically with efficiency optimize.
- Language
enwrapped. User needn’t to encode the SQL statement if they change the
database to different code page.
- DataSet can be
defined to get data from multiple tables, not a single one.
- Some DataSets
that will be used very frequently can be put into buffer, and refresh there
data when necessary.
The major difference against the O-R
mapping solution is there don’t exist the real java class of persistence object
to each table. Only one java type exists, that is DataSet. That is to say,
DataSet is abstraction of table. It can handle all the operation of tables, all
the persistence object is an instance of it.
The reason of handling it like this is
because two point.
- Treating each
table as a java class is hardly to gain any benefit from OO theory
(association, inheritance and polymorphism) because the table design
theory is totally different from OO theory, it is hardly to see a class of
table has any characteristic of association, inheritance and polymorphism.
But treating the concept of table as a java class is just follow the OO
theory, because any table is a child of table. Their operation is same.
- It will be much
easier to build more component on it since we treat table as a common
class, e.g., we can use DataSet as a common data object to transfer in the
whole project, and do any operation on it.
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2. How to use
no introduction at this time. since it is
beta version
pls see Test.java for reference