Relational Database model properties - Database

Q.  What are the properties of Relational Database model?
- Published on 27 Aug 15

a. Data is presented as a collection of relations.
b. Each relation is depicted as a table
c. Each row ( “ tuple ” ) represents as a single entity
d. All of the above

ANSWER: All of the above
 

    Discussion

  • Nirja Shah   -Posted on 02 Nov 15
    A Relational Database Model
    - It is based on the relational model developed by E.F. Codd.

    - It allows the definition of data structures, storage and retrieval operations and integrity constraints.

    - In such a database the data and relations between them are organized into tables.

    - A table is a collection of records and each record in a table contains the same fields.

    - The contents of a table can be permanently saved for future use.

    Properties
    1. Data is presented as a collection of relations.

    2. Each relation is depicted as a table.

    3. Columns are attributes that belong to the entity modeled by the table (ex. In a student table, you could have name, address, student ID, major, etc.).

    4. Each row ("tuple") represents a single entity (ex. In a student table, John Smith, 14 Oak St, 9002342, Accounting, would represent one student entity).

    5. Every table has a set of attributes that taken together as a "key" (technically, a "superkey") uniquely identifies each entity (Ex. In the student table, “student ID” would uniquely identify each student – no two students would have the same student ID).

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