In Milos, there are two different objects that are combined to provide the functionality that is normally referred to as "Business Object". Most of the time, developers will use a type of object known as a "Business Entity". Business Entities are stateful objects that deal with - well - entities. For instance, an entity could be an invoice (a single invoice that is). This would mean that the Business Entity contains information about a single record for the invoice, but also additional records for things such as line items, recipients, addresses, and so forth.

While Business Entities are the most common data access components a developer will interact with, they have no concept of how to talk to a database. Business Entities deal in exposed properties and methods, not SQL Commands. To communicate with a database, a Business Entity needs to be teamed up with a Business Object. No Business Entity can function without a Business Object. One could however use Business Objects on their own. While Business Objects could be used to update information, they are mostly used to retrieve lists of items stored in data sets.

A third type of object, the Data Access Layer, abstracts the details of a specific database back end from the Business Object. This allows the Business Object to ask the back end for a list of line items for an invoice and not care if the names come from Sql Server, MySql or an Excel spreadsheet!

• Why did we create the Milos Data Components?
  
• Business Entities
  
• Business Objects
  
• Data Access Layer