Microcomputer based database packages have become quite affordable to the smallest of firms. Centralised database facilities also expose the firm to greater damage if security is violated. The structures we will look at are the tree structure, network structure, relational structure and flat structure. These structures differ in the way that related data items are linked. Under the tree structure, data sets are represented by a hierarchical structure.
Trees consist of nodes and paths.
The root node is the single point of entry for each tree. From the root node paths connect to more detailed nodes. Importantly, each lower level node is linked to a single higher level node. The tree structure is quite simple, and as such is suitable when the focus of concern is on one entity such as an employee. Because of the simple structure data can be retrieved by the DBMS very quickly.