Logical and physical structures

I. Logical Structure

The relationship between data elements in a data object.

There are four logical structures:

1. Set structure: the data elements in the set structure belong to the same set, and there is no other relationship between them. Each data element is equal, and its common attribute is the same set.

2. linear structure: the data elements in a linear structure are one-to-one relationships.

3. Tree Structure: there is a one-to-many relationship between elements in the tree structure.

4. Graphic Structure: The data elements in the graphic structure are many-to-many relationships.

Ii. Physical Structure

The logical structure of data is stored in the computer.

There are two types of data storage structures: sequential storage and chained storage.

1. Sequential storage: stores data in a sequential address storage unit. The logical and physical relationships between the data are the same.

2. chained Storage Structure: data elements are stored in any storage unit, which can be continuous or not continuous.