Definition: A Data object represents a container for data values, a place where data values may be stored and later retrieved.
Definition: A runtime grouping of one or more pieces of data in a virtual computer.
Definition: A Location in memory with an assignment name in the actual computer.
Data objects can be: •
1) at program execution- Programmer-defined -(example variables, constant, arrays, files etc)
2) not directly accessible to programmer- system defined- run time storage, stacks, file buffers, free space lists.
Data object is usually represented as storage in Computer memory and a data value is represented by a pattern of bits. So we can represent the relation between Data Object and Data value.
A Data Object is elementary if it contains a data value that is always manipulated as a unit.
A Data Object is an Data Structure if it is an aggregate of the data object
Binding and Attributes of Data Object:
Binding is an association of data values and entity.
1) Type: This associates the data object with the set of data values that the object may take.
2) location: This associate the binding of a storage location in memory where the data object is represented. Only storage management routines can only change add data object in the virtual computer.
3) Value: This binding is usually the result of an assignment operation.
4) Name: The binding to one or more names by which the object maybe referenced during program execution is usually set up by declaration and modified by subprogram calls the returns.
5) Component: The binding of a data object to one or more data object of which it is a component is often represented by a pointer value. And may be modified by a change in pointer.
