Ddm/380 Normaliziation
ERD Normalization
Name
DBM 380
April 19, 2010
Instructor
Introduction
Normalization means to organize data and break-down the data into smaller tables, which makes data management an easier process. To avert redundant data, normalization of a database occurs thus making sure data dependencies make sense. Database normalization aids in the identification of potential problems, known as update anomalies in a relational database. Normalization is often disregarded because one may often believe understanding and applying these principles is an intricate task. However, normalization is a non-complicated process as a database that is not normalized will generally be inaccurate, slow, inefficient, and the results might not produce the expected data. Not to mention if you have a normalized database, queries, forms, and reports are much easier to design (Melton, 2002).
Explanation of Normalization The repeating groups in the Driving Log were removed and put in another table. OffDutyStartTime1, OffDutyStartTime1, OffDutyStopTime2, and OffDutyStopTime2 will be placed in a new table called “TimeTable.” Timetable has StartTime, StopTime, and TypeOfTimeID. Note. TypeOfTimeID is a foreign Key referenced in another table. Table “Time Type”: Time_Type_ID | UniqueIdentifer | | Time_Type_Name | Varchar | This can be OffDuty, OnDuty, Driving, Odometer, SleeperBerth, etc. | Co-driver name has been removed from the table “Driving Log” because from the Co_Driver_EmpID one can find the driver’s details. In the “Violations” table State/Municipality_Issuing_Citation is removed and “StateID” has been added. A new table “State” has been created to hold StateID, State/Municipality_Issuing_Citation. Table “State”: StateID | UniqueIdentifer | Examples – NJ, NY, etc. | State/Municipality_Issuing_Citation | Varchar | This
Name
DBM 380
April 19, 2010
Instructor
Introduction
Normalization means to organize data and break-down the data into smaller tables, which makes data management an easier process. To avert redundant data, normalization of a database occurs thus making sure data dependencies make sense. Database normalization aids in the identification of potential problems, known as update anomalies in a relational database. Normalization is often disregarded because one may often believe understanding and applying these principles is an intricate task. However, normalization is a non-complicated process as a database that is not normalized will generally be inaccurate, slow, inefficient, and the results might not produce the expected data. Not to mention if you have a normalized database, queries, forms, and reports are much easier to design (Melton, 2002).
Explanation of Normalization The repeating groups in the Driving Log were removed and put in another table. OffDutyStartTime1, OffDutyStartTime1, OffDutyStopTime2, and OffDutyStopTime2 will be placed in a new table called “TimeTable.” Timetable has StartTime, StopTime, and TypeOfTimeID. Note. TypeOfTimeID is a foreign Key referenced in another table. Table “Time Type”: Time_Type_ID | UniqueIdentifer | | Time_Type_Name | Varchar | This can be OffDuty, OnDuty, Driving, Odometer, SleeperBerth, etc. | Co-driver name has been removed from the table “Driving Log” because from the Co_Driver_EmpID one can find the driver’s details. In the “Violations” table State/Municipality_Issuing_Citation is removed and “StateID” has been added. A new table “State” has been created to hold StateID, State/Municipality_Issuing_Citation. Table “State”: StateID | UniqueIdentifer | Examples – NJ, NY, etc. | State/Municipality_Issuing_Citation | Varchar | This
References: Melton, B. (2002). Databases: Normalizing Access Data. Retrieved from http://pubs.logicalexpressions.com/Pub0009/LPMArticle.asp?ID=88