Table of Contents
Features of relational database 3
Entity and attribute 3
Referential Integrity 6
Errors that can be encountered 8
This paper talks about how features of modern database can be useful in the modern business. It also talks about how they work and their importance and advantages without forgetting the errors that might be encountered. The purpose of this paper is to convince Modern Fishing Company to move to better ways of Data management. The findings of this paper state that the features of relational database can be used to ...view middle of the document...
In this kind of a database, an attribute appears with the entity when it is needed to, when one searches for it. If MFC needs their data do be available or found in a blink of an eye, relational database is their answer. Figure 1, bellow shows how an entity and an attribute might appeartogether in a database.
Figure 1 is an example of a table in a database. In this table, â€˜Customer Nameâ€™ field is the entity since it is a person. And the other fields adds information regarding the entity, those are the attributes of the customers.
The researcher found out that another feature of relational database is Validation Rule. A validation rule is a set of rules that only allows the user to input a certain type of character or a certain amount of character in a given field. This means that the validationrule is a means of checking data accuracy and appropriateness when a user inputs data. Validation rules can be used to specify what data is required to be typed in. When the user inputs inappropriate characters in the field. An error message will pop up. This error message is set when the database designer creates the validation rule.
â€œThe value of the Validation rule property is a string containing an expression that is used to test the userâ€™s input. The expression used as a fieldâ€™s Validation rule property cannot contain user-defined functions or any of the access domain or aggregate functions. A fields Validation Rule cannot reference forms,queries, or other tables in the application.â€ - Access 2007 Bible, By Michael R. Groh, Joseph C. Stockman, Gavin Powell, Cary N. Prague, Michael R. Irwin, Jennifer Reardon.
If MFC wants their data to be more valid, to reduce the chances of errors in their fields of records and to limit a user input into their data, they should move away from Excel Spreadsheets to modern ways of database management.
In a modern SQL database or any other, there are certain fields on a table that are purposed for Entity or Data identification. These fields are unique in a table that represents the entry on another table. These are called Keys. When a data or an entry is given an ID that uniquely identifies it in a table, it is called a Primary Key. According to Carlos Coronel and Steve Morris in the Database design, the most important characteristic of an entity is its primary key, which uniquely identifies the entities. He continued â€“ â€œThe keys function is to guarantee entity integrity.â€
For an example, in this scenario, in employees table, â€˜EmployeeIDâ€™ should be the primary key for this certain table. It is a must for a user to input appropriate data on this field. However important this field is, it is still an attribute of the customer.
Another type of a key is a Foreign Key. This is a primary key on a table that is in another table.
Mr. Coronel and Mr. Morrison did say something about these types of keys.
-â€œPrimary keys and foreign keys work together to implement...