Database systems and Administration Essay Example | Topics and Well Written Essays - 4000 words

Database systems and Administration - Essay Example These three tables handle information regarding products being developed by the organization, countries in which it operates and employees that work for the organization. Since the organization sells various kinds of batteries it is evident that to maintain the record of the sales it makes it would need a sales table. The organization would also have to maintain the record of inventory and the products that are available. Finally to maintain records regarding the wages and designation of each employee a separate table of Job is created to help evaluate the position of an individual within the organizational structure. To help distinguish each entity from the other each record within each entity is assigned a unique alphanumeric character that helps in distinguishing one record from the other. Other entities that is present within a certain table further help in elaborating the data regarding a particular record. For example in the country table the attributes of country name and coun try description allows an individual to understand what the country ID stands for. These fields can significantly aid the organization when they are carrying out a presentation or are creating their annual reports that need to be presented to the organizational heads of the organization. Integrity rules: The relational tables are shown below: Product Inventory No Attribute name 1 Inventory ID 2 Product ID 3 Country ID 4 Quantity Sales No Attribute name 1 Transaction ID 2 Money Obtained 3 Products shipped 4 Product ID Employee Country No Attribute name 1 Country ID 2 Country Description 3 Country Name Department No Attribute name 1 Department ID 2 Department Name 3 Country ID Job No Attribute name 1 Job ID 2 Description 3 Qualification required 4 Salary The rules of integrity are given as follows: Primary keys for each record must be unique, cannot be null and must be in accordance to the data variable set for it. A unique primary key helps in distinguishing one record from the other . The value of a foreign key that is present within another table must be in accordance to the value that is present in the table where that particular field is the primary key. In short the value placed in a foreign key field must also be present in the field where it is a primary key. An employee cannot be assigned more than one country ID against his or her record. This means that an employee would only be assigned the country ID in which he or she works. This would help prevent any confusion that may arise from the fact that an employee is incharge of two departments that exist in different countries. Issues due to the use of un-normalized tables: The use of un-normalized database may cause a great deal of confusion while updating the data. If one of the users has accessed a particular record that is present i