Assignment 3: Understanding the Basics of Databases
CIS 106 – Introduction to Information Technology
Understanding the Basics of Databases
Databases are used to organize a collection of data, allowing for easy access, retrieval, and use of information. The first databases were slow at processing information and inconsistent when applications would require the same information, but kept in different files. Relational databases, normalization, and Structured Query Language have improved the efficiency of databases. To be a proficient database programmer, one should have a basic understanding of rational databases, normalization, Structured Query ...view middle of the document...
By reducing redundancy, the data is simplified and uses less disc space. When a database is normalized, it is broken into smaller tables, making it easier to modify. It takes less effort to make changes to a small table with little data than it does to change a massive table with all of the database data. Even the largest databases had to start from a basic concept before developed into a physical database.
When creating a database, there are three data models produced while progressing from basic requirements to the actual database. These database models are the conceptual, logical, and physical (West, 2011). The conceptual data model is an abstract and basically a map of concepts and their relationships used for databases. The conceptual model focuses on what data is required and how it should be organized - what tables should exist, and the connections between them. In this phase entities are recognized, and the relationships between them. The conceptual model is then translated into a logical data model.
The logical database model is when the table columns in each table are explicitly defined. “Logical database design develops a conceptual model of the database from a set of user requirements and refines that model into normalized SQL tables” (Lightstone, Teorey & Nadeau, 2007). Normalization occurs at this level in order to reduce redundancy and improve performance. In as much detail as possible, a logical data model describes the data without any concern of how it will be physical implemented.
The physical data model is the last step in data modeling and is the physical structure of the database, how the model will be built. It is the lowest level of abstraction. The physical model organizes data into tables, access to accounts, performance and storage details (West, 2011). The purpose of the physical design is to maximize the performance of the database. To access and manage databases, a standard language was developed, called Structured Query Language (SQL) (Agarwal & Huddleston, 2008).
Structured Query Language