Websharp use Instructions (4)

How Web data is accessed

The purpose of data access is to persist the saved object. In Websharp, the PersistenceManager interface is defined to implement this function. PersistenceManager definition can be seen: attached 1:websharp main interface definition--persistencemanager



We can persist an object by using the following methods:

Product Product=new product (TRUE);

...//Processing product

PersistenceManager pm = persistencemanagerfactory.instance ().

Createpersistencemanager ();

Pm. Persistnewobject (P);

Pm. Close ();




The code is very concise and intuitive, not a lot of database manipulation code, it is not easy to error.

You can also initialize a persistencemanager by passing a persistenceproperty parameter to Persistencemanagerfactory, such as:

Persistenceproperty pp=new Persistenceproperty ();

pp......//Set properties of PP

PersistenceManager pm = persistencemanagerfactory.instance (). Createpersistencemanager (PP);


For a description of Persistenceproperty, see the following system Persistence configuration information section.



Transaction processing

In many cases, when dealing with object preservation, we need to use transaction processing, especially when dealing with a One-to-many structure object similar to a warehouse receipt in the previous example. In Websharp, we can accomplish this function through the transaction interface. Transaction interface definition can be seen: attached 1:websharp main interface definition--transaction

Here is an example of using transaction processing:

Product Product=new product (TRUE);

...//Processing product

PersistenceManager pm = persistencemanagerfactory.instance ().

Createpersistencemanager ();

Transaction trans=pm. Currenttransaction;

Trans. Begin ();

Try

{

Pm. Persistnewobject (P);

Trans.commit ();

}

catch (Excption e)

{

Trans. Rollback ();

}

Finally

{

Pm. Close ();

}