Reltional databases - Relational Database Concepts Learning...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Relational Database Concepts Learning objective After completing this topic, you should be able to describe relational database concepts. 1. An introduction to relational databases A relational database comprises a collection of related data in tables. Users can access and modify data in a database, depending on their permissions. Dr. Edgar Codd introduced the relational database model in a paper entitled "A Relational Model Data for Large Shared Data Banks" in 1970. In his paper, Codd identifies 11 rules that provide a standard method for determining whether a database is relational. And these rules are designed to reduce data redundancy and ensure data integrity. Codd's rules are based on the premise that the data in a database should be stored in tables. According to these rules, you should be able to locate an entry in a table based on the table name, field name, and primary key value. Question What do you think are the advantages of using the relational database model? Options: 1. It has a 3-D architecture 2. It is stable 3. It comprises a wide selection of relational database products 4. It uses referential integrity and constraints to protect data Answer The advantages of a relational database are that it is stable, comprises a wide selection of relational database products, and uses data referential integrity and constraints to protect data. 2. Fundamental concepts The relational database model is based on the following concepts: data independence
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
simple structure set-oriented processing To ensure data independence, the relational database model differentiates between the logical and physical aspects of database management. Using a simple structure for a relational database enables users to share information about the data easily. A set-oriented relational database enables the processing of multiple sets of records for a single statement query. The main components of the relational database model include its structure manipulations behavior The structure of the relational database model is based on a relation or a table of data. The relational model is not based on relationships or connection between tables. The relational database model consists of manipulations or a series of operators that you can use to convert one set of relations to another. Question Which of the following do you think regulates the behavior of a relational database model? Options: 1. A set of operators that transforms relations 2. Integrity rules that protect the consistency of a database 3. The relationships between the data 4. A tabular structure Answer The integrity rules, which protect the consistency of the database, regulate the behavior of a relational database model. Question
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/22/2009 for the course DBST DBST 651 taught by Professor Yelena - ta during the Spring '09 term at MD University College.

Page1 / 70

Reltional databases - Relational Database Concepts Learning...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online