Explain What Is Meant By Repetition Of Information And Inability To R

1.	Explain What Is Meant By Repetition Of Information And Inability To Represent Information. Explain Why Each Of These Properties May Indicate A Bad Relational Database Design?
Answer» Repetition of information is a condition in a relational database where the values of one attribute are DETERMINED by the values of another attribute in the same relation, and both values are repeated throughout the relation. This is a bad relational database design because it increases the storage required for the relation and it MAKES updating the relation more difficult. Inability to REPRESENT information is a condition where a relationship exists among only a proper subset of the attributes in a relation. This is bad relational database design because all the unrelated attributes must be filled with null values otherwise a TUPLE without the unrelated information cannot be inserted into the relation. Loss of information is a condition of a relational database which results from the decomposition of one relation into two relations and which cannot be combined to recreate the original relation. It is a bad relational database design because certain queries cannot be ANSWERED using the reconstructed relation that could have been answered using the original relation.

Explain What Is Meant By Repetition Of Information And Inability To Represent Information. Explain Why Each Of These Properties May Indicate A Bad Relational Database Design?

Answer»

Repetition of information is a condition in a relational database where the values of one attribute are DETERMINED by the values of another attribute in the same relation, and both values are repeated throughout the relation. This is a bad relational database design because it increases the storage required for the relation and it MAKES updating the relation more difficult.
Inability to REPRESENT information is a condition where a relationship exists among only a proper subset of the attributes in a relation. This is bad relational database design because all the unrelated attributes must be filled with null values otherwise a TUPLE without the unrelated information cannot be inserted into the relation.
Loss of information is a condition of a relational database which results from the decomposition of one relation into two relations and which cannot be combined to recreate the original relation. It is a bad relational database design because certain queries cannot be ANSWERED using the reconstructed relation that could have been answered using the original relation.