Accessing data

In program environments as C++, .NET, JAVA or PHP, access to data is managed by Property and Value handles. Property and value handles provide the lowest level in the access hierarchy.

Property and value handles can be used for accessing persistent data as well as transient. You may use property handles for iterating through a collection, and value handles for accessing elementary values (attributes) in an object instance.

For reading, creating, updating or deleting object instances, property handles are required as well. Besides simple data manipulation functions, property handles allow locking instances, support event handlers and transactions, provide metadata etc.

Value handles allow updating values, provide data conversion, metadata as well and other functions.

This chapter explains the basic functionality required for accessing data in a ODABA database. Advanced features are described in the next chapter and details about how to use property and value handles in details are described in the class reference.