Question

d- What is the purpose of a feasibility study (or feasibility analysis)?

e- What is one advantage and one disadvantage of a centralized database compared to a distributed database?

f- What is the deletion anomaly problem that databases try to avoid?

g- One problem that good database designs try to solve is the "data insertion problem." What is the data insertion problem?

Answer 1

d- What is the purpose of a feasibility study (or feasibility analysis)?

Feasibility study is the feasibility analysis or it is a measure of the project in terms of how much beneficial product development will be for the organization in a practical point of view. Feasibility study is carried out based on many purposes to analyze whether software product will be right in terms of development, implantation, contribution of project to the organization etc.
Feasibility study is so important stage as after completion of feasibility study it gives a conclusion of whether to go ahead with proposed project as it is practically feasible or to stop proposed project here as it is not right/feasible to develop or to think/analyze about proposed project again. Along with this Feasibility study helps in identifying risk factors involved in developing and deploying system and planning for risk analysis also narrows the business alternatives and enhance success rate analyzing different parameters associated with proposed project development.

e- What is one advantage and one disadvantage of a centralized database compared to a distributed database?

A centralized database is basically a type of database that is stored, located as well as maintained at a single location only. This type of database is modified and managed from that location itself. This location is thus mainly any database system or a centralized computer system.

When centralized databse is compared to distributed database, The data access time in case of multiple users is more in a centralized database, while the data access time in case of multiple users is less in a distributed database which is considered as a disadvantage when it comes to centralized database.

The management, modification and backup of centralized database is easier as entire data is present at the same location but the same for distributed database is very difficult as it is spread across different physical locations. This is considered as an advantage when it comes to centralized database.

f- What is the deletion anomaly problem that databases try to avoid?

A deletion anomaly occurs when you delete a record that may contain attributes that shouldn’t be deleted. Deletion anomalies happen when the deletion of unwanted information causes desired information to be deleted as well. For example, if a single database record contains information about a particular product along with information about a salesperson for the company and the salesperson quits, then information about the product is deleted along with salesperson information. To avoid these kinds of deletion problems, we need to decompose the original table into several smaller tables where each table has minimal overlap with other tables.

g- One problem that good database designs try to solve is the "data insertion problem." What is the data insertion problem?

Data insertion problems contributes to the creation of redundant data. Redundancy means having multiple copies of same data in the database. This problem arises when a database is not normalized. Data redundancy is the existence of data that is additional to the actual data and permits correction of errors in stored or transmitted data. The additional data can simply be a complete copy of the actual data, or only select pieces of data that allow detection of errors and reconstruction of lost or damaged data up to a certain level. Data redundancy leads to data anomalies and corruption and generally should be avoided by design. Applying database normalization prevents redundancy and makes the best possible usage of storage. An Insert Anomaly occurs when attributes cannot be inserted into the database without the presence of other attributes.