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DATA MODEL - Coggle Diagram
DATA MODEL
Degrees of Data Abstraction
Conceptual
It represents a global view of the entire database.
Integrates all external views into a single global view.
It is the basis for identification and high-level description of the main data objects.
It provides a relatively easily understood view of the data environment.
It is independent of both software and hardware.
Internal
Represents the database as seen by the DBMS
Maps the conceptual model to DBMS
Internal schema depicts a specific representation
of an internal model
Software dependent and hardware independent
Logical independence: Changing internal model
without affecting the conceptual model
External
Easy to identify specific data required to support each business unit's operations
Facilitates designer's job by providing feedback about the model's adequacy
Creation of external models helps to ensure security constraints in the database design
Simplifies application program development
Relational Model
Disadvantages
Requires substantial hardware and system software overhead
Conceptual simplicity gives untrained people the tools to use a good system poorly
May promote information problems
Advantages
Structural independence is promoted using independent tables
Tabular view improves conceptual simplicity
Ad hoc query capability is based on SQL
Isolates the end user from physical-level details
Improves implementation and management simplicity
Hierarchical Model
Disadvantages
requires knowledge of physical data storage characteristics
changes in structure require changes in all application programs
implementation limitations
no data definition
navigational system requires knowledge of hierarchical path
lack of standards
Advantages
database security provided & enforced by DBMS
promotes data sharing
efficient with 1:M relationships
parent/child relationship promotes conceptual simplicity
Network Model
Advantages
data access is flexible
handles more relationship
conceptual simplicity
data owner/member relationship promotes data integrity
conformance to standards
includes data definition language (DDL) and data manipulation language (DML)
Disadvantages
navigational system yields complex implementation, application development, and management
structural changes require changes in all application programs
system complexity limits efficiency
NoSQL
Disadvantages
Need to use huge databases
Not mature and less support
Requires multiple databases
Difficult to maintain
Not having standard query language
Advantages
Integrated search functions provide high-quality ranked search results
The expansion of NoSQL incredibly cheap and easy
Can often out perform SQL databases simply
Easy to store high-variability data
Modular architecture allows components to be exchanged
Object-Oriented Model
Disadvantages
Object database are not widely adopted
The high complexity can cause performance problems
Lack of support for security
Lack of universal data model
Advantages
Complex and sets can be save and retrieved quickly and easily
Capable of handling a large variety of data types
Applicability to advanced database app
Object IDs are assigned automatically
Object-Oriented Model works well with Object-Oriented Programming languages.