Database I
ISM 6215 - Business Database Systems I
Fall 2013
Home Work – 1
(Marks 100)
Question 1 - Contrast the following terms. Give one example of each
1. Degree versus cardinality of relationship
2. Required versus optional attributes
3. Data dependence versus data independence
4. Structured versus unstructured data
(4*2.5 =10 marks)
Answer 1 -
Degree; cardinality. The degree (of a relationship) is the number of entity types that participate in that relationship, while cardinality is a constraint on the number of instances of one entity that can (or must) be associated with each instance of another entity. You may give an example of movie versus DVD – degree is two and cardinality is one to many.
Required attribute; optional attribute. A required attribute must have a value for each entity instance, whereas an optional attribute may not have a value for every entity instance. You may give an example of degree versus major in student entity in a University student registration system – degree is mandatory attribute and major is optional.
Data dependence; data independence. With data dependence, data descriptions are included with the application programs that use the data, while with data independence the data descriptions are separated from the application programs. Give example of file processing system versus database systems. In file processing systems, the applications have to incorporate the data description of files and the logic to access them.
Structured data; unstructured data. Structured data refers to facts related to objects and events of importance in the user’s environment and represent the traditional data that is easily stored and retrieved in traditional databases and data warehouses. Unstructured data refers to multimedia data, such as images, sound and video segments that are now stored as part of the user’s business environment.
Data; information. Data consist of facts, text, and other multimedia objects, while
Fall 2013
Home Work – 1
(Marks 100)
Question 1 - Contrast the following terms. Give one example of each
1. Degree versus cardinality of relationship
2. Required versus optional attributes
3. Data dependence versus data independence
4. Structured versus unstructured data
(4*2.5 =10 marks)
Answer 1 -
Degree; cardinality. The degree (of a relationship) is the number of entity types that participate in that relationship, while cardinality is a constraint on the number of instances of one entity that can (or must) be associated with each instance of another entity. You may give an example of movie versus DVD – degree is two and cardinality is one to many.
Required attribute; optional attribute. A required attribute must have a value for each entity instance, whereas an optional attribute may not have a value for every entity instance. You may give an example of degree versus major in student entity in a University student registration system – degree is mandatory attribute and major is optional.
Data dependence; data independence. With data dependence, data descriptions are included with the application programs that use the data, while with data independence the data descriptions are separated from the application programs. Give example of file processing system versus database systems. In file processing systems, the applications have to incorporate the data description of files and the logic to access them.
Structured data; unstructured data. Structured data refers to facts related to objects and events of importance in the user’s environment and represent the traditional data that is easily stored and retrieved in traditional databases and data warehouses. Unstructured data refers to multimedia data, such as images, sound and video segments that are now stored as part of the user’s business environment.
Data; information. Data consist of facts, text, and other multimedia objects, while