Essay on Databases: Database Normalization and Data

Submitted By Gwest52
Words: 1490
Pages: 6

Databases: Concept, Design, and Functionality

A relational database is a maintained collection of separate, related tables containing data stored in fields (columns) called attributes and records (rows) called records (Definition Rel DB, 2014). Relationships between the tables are created by utilizing a common field or key. Keys are data points used to identify unique values or records within tables, and provide a logical method to access a record within the table (Gilfillan, 2002). A primary key is a qualifier chosen to identify a unique individual record in a particular table. The table containing the primary key is related to one or more additional tables utilizing fields that are common to them (Gilfillan, 2002). This common field must be the primary key for the related table and is called a foreign key. Foreign keys allow the relation between the tables and secure the integrity of the data referenced. Foreign keys also allow the user to delete or update the database by removing or amending a record in one table which then cascades through relevant tables executing the deletion or update (Gilfillan, 2002).
The use of a database management system (DBMS) allows the user to store, maintain, and retrieve information using transactions. Transactions are one or multiple SQL statements(s) that compose a logical entity of work (Oracle, 2014). The use of relational databases allows entities to store large amounts of information in a standardized process, manage the stored data in an efficient manner, and access the relevant, up-to-date information using a simple query. Relational databases enable users, through the use of targeted queries, quickly to retrieve the pertinent information related within the database without conducting multiple searches through data files. Use of relational databases streamlines data entry, records maintenance, and access to information thereby increasing productivity and reducing redundancy through the elimination of duplication (effort and data storage).
Normalization is the mechanism in which data contained in the database is organized, removing inconsistencies and redundancies to protect the data content and make the database more flexible (Microsoft, 2013). Database experts developed a number of rules, known as normal forms, devised to eliminate errors during normalization. Normal forms are incorporated to assess and correct table structure to reduce data redundancies, thereby decrease the chance for anomalies (Carpenter, 2008). There are seven normal forms; however, only three are recognized as critical in the development of a properly functioning database.
The first normal form involves the removal of repeating data, ensuring each attribute expresses only a single value, arrays/groups are not repeated, and that each record is unique. Do not use multiple fields in one table to store like data, use separate tables when needed, identifying the related datasets with a primary key (Microsoft, 2013).
The second normal form eliminates functional discrepancies, related attributes within a table that are dependent on one another and not solely on the key. By utilizing rules for the second form, separate attributes should be given their own entities to remove functional discrepancies thereby ensuring members are dependent on the key. Create a separate table for sets of values that apply to several records and relate the tables with a foreign key (Microsoft, 2013).
Third normal form seeks to eliminate transitive dependencies, attributes that are dependent on another attribute for its meaning, instead of the primary key. Every attribute should describe the entity, not another attribute. Eliminate or move, (new table), attributes that are not dependent on the primary key (Sarkar, 2006).
Normal forms 4 through 7, Boyce-Codd Normal Form (BCNF), fifth normal form (Project-Join Normal Form), sixth normal form, and Domain-Key Normal Form (DKNF) are higher normal forms and not used as…