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A relational database is a database that consists of a collection of tables with columns showing entities, and rows showing data. This type of database uses a primary key and foreign key. The foreign key in another table will point to the primary key of a table, and this is how tables can relate to each other. This permits for one-to-one, one-to-many, and many-to-many relationship between the data. An advantage of relational databases includes the ease of adding or modifying new tables and entities without needing to change the structure of the database already in place. Relational database have many features, including indexing, setting data type, and setting validation tests, all these help to ensure data integrity.

I am feeling that I am learning the DBMS and RDBMS in details as the week passes on. In addition, I feel I am gaining more knowledge on Database Management System. I am somewhat confident to develop the relation with appropriate attribute and constraint.

4- Item Table - The Item Table stores information pertaining to products that may appear on an order. It describes goods that can be purchased from a Store.

The challenging part was actually trying to understand what will be the best way to break a relation down into multiple relations without jeopardizing the integrity of the data at the same time. As I mention before it is not hard to do it but you really have to know how to do it.

When it comes to the data model, there exists a relationship that has three different representations for the reason that database requires the relationship between the tables. It goes hand-in-hand with one another without the relationship the tables would have no purpose. The information cannot be repetitive in order for the each table to work and provide the specific database that is related to the information. In different ways the tables in the Huffman Trucking Fleet Truck database

A(n) FOREIGN KEY constraint is used to ensure that referential integrity exists between tables. _________________________

In addition, the primary keys that are preserved will need to be configured as required fields, and there are several primary keys that can be replaced with Auto-Number Identities. The Inventory table will also need to be modified to indicate what quantities are on hand at each individual store. Under the current database, there is no visible way to show which store has inventory. For example, one store may have 35 boxes of Frog Legs, while there may be two other stores that are out of stock.

Foreign key constraints can be used to define required relationships between and with tables. When a foreign key constraint is added to an existing column or columns in the tables SQL server, by default the process will check the existing data in the column to ensure that all values, except NULL, exist in the column(s) of the referenced primary key or unique constraint.

The entity integrity constraint says that if a relation R2 includes a foreign key FK matching the primary key PK of other relation R1, then every value of FK in R2 must either be equal to the value of PK in some tuple of R1 or be wholly null.

Answer: This operation can’t be used. Because Pnumber has been used as a foreign key of WORKS_ON relation and deleting record with Pname = ‘ProductX’ will also delete product with Pnumber = ‘1’. Since this value has been used in WORKS_ON table so deleting this record will violate referring integrity constraint. If we want to delete this data than we also have to delete data from corresponding tables.

Note also that the *:* relationship has been broken down into two 1:* relationships for which the BENEFIT table serves as the composite or bridge entity.

You have been asked to create two conceptual database models using MS Visio Database Model Diagram Template. The purpose of this lab is to have you gain familiarity with the various modeling tools needed to create a conceptual model (entity relationship diagram) of a database. You will create two conceptual models.

Your construction company currently tracks all of its information in an Excel spreadsheet. However, some information has become quite difficult to track and add in this spreadsheet, so the company has decided to move toward using a database instead. The current spreadsheet data example is as follows:

The main feature of a relation database would be the primary key. It is a unique identifier set to each and every record which moves across different tables in relationships. A good example of a primary key is a Social Security number. The primary keys job is to make each record unique and lets data to be kept in more than one table. Each table within a relational database will have to have a field for the primary key.

Creating a database of suppliers and ingredients will enable you to manage ingredient pricing more effectively.