I need help! I have my ERD yet I must create a functional-relation schema, funct
ID: 3794307 • Letter: I
Question
I need help! I have my ERD yet I must create a functional-relation schema, functional dependencies diagram, and relational model based on my ERD. These diagrams/models are very confusing to me and would greatly appreciate the help.
ERD:
Customer Information Employee Nane, address, contact Employee Wmber Salary customer finds produdt Product when redeved payment emplayee ships ord Payment Payment Option employee finds the arder Product Type Vendlor Price Peyment Total Banking Information ustomer orders product Orde- Order Detail mpocessing details otro ing detsils af airder Proat Detal Order Totsl Order Tots PaymentExplanation / Answer
Entity relationship diagram (ERD) is one of the most widely used technique for data modeling. Data modeling is an essential component of database design and development. It provides a means to analyze business requirements so as to standardize organizational vocabulary, enforce business rules, and ensure adequate data quality. Since data has become a vital corporate resource (Adelman et al., 2005; Dyche, 2000; Liataud & Hammond, 2001), good data models can make a significant contribution to an organization’s future success.
Data modeling is performed during the initial phases of the database development processDuring this process, the top two phases are concerned with the information content of the database, while the last two phases are concerned with the implementation of the database on some commercial DBMS.
Normalization utilizes association among attributes within an entity table to accomplish its objective. Since an ERD also utilizes association among attributes as a basis to identify entity type structure, it is possible to apply normalization principles during the conceptual data modeling phase. Performing normalization during ERD development can improve the conceptual model, and speed its implementation. This paper outlines the application of normalization principles to ERD development during the conceptual modeling phase. There are various standards for ERD. In this paper, the Crow’s Foot notation is utilized.
The ERD has received many extensions and variations, which are generally termed as Enhanced Entity Relationship (EER) model (Lenzerini & Santucci, 1983; Lenzerini & Nobili, 1990; Thalheim, 1998; Balaban & Shoval, 1999; Balaban & Shoval, 2002). In the last few years, the Unified Modeling Language (UML) emerged and became the defacto industry standard for many aspects of object modeling
Data modeling is an iterative process. Generally a preliminary data model is constructed which is then refined many times. There are many guidelines (rules) for refining an ERD. Some of these rules are as follows (Mannino, 2006):
Application of normalization principles toward ERD development enhances these guidelines. To understand this application (i) representation of dependency concepts in an ERD is outlined, followed by (ii) representation of normal forms toward the development of entity type structure. Guidelines for identification of various dependencies is avoided in the paper so as to focus more on their application. Only the first four normal forms and the Boyce-Codd normal forms are considered.
Instead of applying normalization principles during the relational design portion of logical database design phase, it is better to apply them during the conceptual modeling phase. Due to the similarity in the notion of an entity type and a relation, normalization concepts when explained or applied to an ERD may generate a richer model. Also, such an application enables a better representation of user working requirements. This application now results in the specification of additional guidelines for refining an ERD. These guidelines can be stated as follows: