Describing & Storing Data from Dbms
Assignment
of
DBMS
Topic: Describing & Storing Data In DBMS
(Traditional Models)
Introduction
A computer database relies upon software to organize the storage of data. This software is known as a database management system (DBMS). Database management systems are categorized according to the database model that they support. The model tends to determine the query languages that are available to access the database. A great deal of the internal engineering of a DBMS, however, is independent of the data model, and is concerned with managing factors such as performance, concurrency, integrity, and recovery from hardware failures. In these areas there are large differences between products.
A Relational Database Management System (RDBMS) implements the features of the relational model outlined above. In this context, Date's "Information Principle" states: "the entire information content of the database is represented in one and only one way. Namely as explicit values in column positions (attributes) and rows in relations (tuples). Therefore, there are no explicit pointers between related tables."
Definition of Describing & Storing Data in DBMS
The user of a DBMS is ultimately concerned with some real-world enterprise, and the data to be stored describes various aspects of this enterprise. For example, there are students, faculty, and courses in a university, and the data in the university database describes these entities and their relationships.
There are three types of describing & storing data in DBMS:
Data Models
Level of Abstraction
Data Independency
Data Models
A database model or database schema is the structure or format of a database, described in a formal language supported by the database management system. Schemas are generally stored in a data dictionary. Although a schema is defined in text database language,
of
DBMS
Topic: Describing & Storing Data In DBMS
(Traditional Models)
Introduction
A computer database relies upon software to organize the storage of data. This software is known as a database management system (DBMS). Database management systems are categorized according to the database model that they support. The model tends to determine the query languages that are available to access the database. A great deal of the internal engineering of a DBMS, however, is independent of the data model, and is concerned with managing factors such as performance, concurrency, integrity, and recovery from hardware failures. In these areas there are large differences between products.
A Relational Database Management System (RDBMS) implements the features of the relational model outlined above. In this context, Date's "Information Principle" states: "the entire information content of the database is represented in one and only one way. Namely as explicit values in column positions (attributes) and rows in relations (tuples). Therefore, there are no explicit pointers between related tables."
Definition of Describing & Storing Data in DBMS
The user of a DBMS is ultimately concerned with some real-world enterprise, and the data to be stored describes various aspects of this enterprise. For example, there are students, faculty, and courses in a university, and the data in the university database describes these entities and their relationships.
There are three types of describing & storing data in DBMS:
Data Models
Level of Abstraction
Data Independency
Data Models
A database model or database schema is the structure or format of a database, described in a formal language supported by the database management system. Schemas are generally stored in a data dictionary. Although a schema is defined in text database language,