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An object type is identified by a noun and in some cases it may be strong or weak entity class. A Strong object type is represented by a triangle and a weak entity class by a triangle inside another triangle. Attributes collectively represent the object class. Attributes by themselves are meaningless and cannot clearly define themselves. In the Visio diagrams, they are usually symbolized by an oval.
Attributes are what is stored in the database hence gives a clear view of how the database would appear. Example: student has a student Id, name and course. In the above example, student is the entity class and student Id, name and course are attributes. Some attributes have a primary key. The key is preferably composed of only a single attribute, but in some cases, more than one.
The final element of entity relation diagram is the relationship. Entities have relationships between them and should be represented where appropriate. Relationship are represented by a diamond and two connecting lines.
Business rule is a statement that imposes some constraint on some particular aspect of the database. You base a business rule based on the organization views and usage of its data, which you determine from the way in which the body performs or conducts its affairs.
Ways of doing things are unique and has different requirements in each group. An example is a club having more than one student and the student not being a member of more than one club. Therefore, there is a constraint on the student’s membership on a given number of clubs (Andreescu & Mircea, 2012).
First, the course can have more than one student partaking it and more than one student can be part of the course. It means, many students will be taking a course, and a student can also do many courses.
Secondly, more than one student can be taught by an instructor, and only one instructor can teach many students.
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The final stage is the mapping of the Global Model to the other applications. The mapping will be able to show the relationship that exists between different entities within the organization. Company Selection The company selected for this project is Budget Transportation firm.
Each book has a book number, title, the number of pages of the books, the name of the publisher, the year of publishing, and list of authors of the book. Each library could own zero to several copies of the same book. The database might store the author's name of each book and other information.
The Relational Database specification required nine table in the following relationships. A table Textbook with a many-to-many relationship through a junction table (outside join) to the table Module through the Module_Detail table. A many-to-many relationship is required between Module and Field through a join table (outer join or junction table) Field_Detail.
Each asset is regularly inspected, and the date of the inspection, the person who carried out the inspection and details of any maintenance actions are noted. If the asset is a photocopier then the toner is replaced and the total number of copies made is recorded as well as the toner serial number.
The most apparent instance of a non computerized database is a telephone directory. On the other hand, telephone companies at the present time make use of an electronic database program to turn out their
It then highlights how the design confirms the three forms of normalization i.e. 1NF, 2NF and 3NF. In order to test the working of the proposed logical design, results of certain test cases have also been presented.
A major pitfall exists in the payment duration; the buyer’s payment can take up to a fortnight since it goes through Ubid which can cause a serious cash flow problem for the new sellers.
E-bid auction is one of the largest auction sites in the UK. It is the second
The unit has enabled me gain substantial knowledge on design and management of database.
The course gives a detailed introduction of database design. The introduction to database design gave me in-depth
There is a storage space of data warehouses for maintaining the historical in addition to the most recent data. This historical data is designed to develop and enhance diverse fads and records available to the senior management in a way that the management makes use of the
Content of one DPD total chlorine powder pillow powder was then added and the readings taken
In conclusion, the concentration of iron in the Lake Water and secondary treatment water is the same. While the total chlorine water in pool
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