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DBMS Organization
DBMS Organization
Hierarchical Database
- Similar to an organizational chart of a
business.
- Fields or records are structured in nodes (modules).
- Nodes are points connected like branches of an upside-down tree.
- Nodes farther down the system are subordinate to the ones above.
- Each entry has one parent node directly above it, and may have
one, none, or several child nodes directly below it.
- A node can be both a parent and a child.
- This type of organization is harder to update, especially when a node
is added or deleted.
Network Database
- Hierarchical arrangement of nodes but each child node
may have more than one parent.
- There are additional connections between parent nodes and child nodes
called pointers.
- Pointers make it possible to reached a node through more than one
path.
- More flexible and more efficient than the hierarchical arrangement.
Relational Database
- The most flexible type of database organization.
- Elements are stored in different tables, each of which consists of
rows and columns.
- Each table is called a relation.
- All related tables must have a key field.
- Makes it possible to link data from two or more database files into
meaningful information.
- Data can be easily added, deleted, and modified.
- Examples of relational databases for microcomputers are dBase,
Access, Paradox and RBase.
- Also used on mainframe and minicomputer Systems.
Object-Oriented Database
- A new, more flexible
type of data base organization.
- Able to
keep track of structured data such as names, address, phone numbers, etc.
- Able to keep track of unstructured data such as photographs, graphics,
audio and video.
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