SL vs DAL, one example of how they are different is that:
let's say we have a DAO for accessing a Customer entity a DAO for accessing Account entity a DAO for accessing History/Trend entity // maybe not a good example, but just three separate entities a Service(object) living in a ServiceLayer, needs to access these three entities, analyze them and based on a current condition, apply a policy, and then notify the interested parties. the Logic for sending Notification is in another Object. the Logic for Accessing/Finding those entities are in another object. our Service(object) responsibility is to perform some operation, with the help of those other objects. (through collaboration). in this case, our Service is not just a basic CRUD. to complicate things further, (in a real world scenario), not all of the data might come from same DataStore, one using a local DataStore, one a WebService to retrieve realtime data, so when going beyond basic CRUD, the need for a Separate(isolated) ServiceLayer and DataAccessLayer, becomes more obvious. -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
