 Show ACIT 1630 Relational Database Design and SQL Review Questions Chapter 3 Yazdon Azhdari A00895515 Taylor Nguyen A01053462 Paul Chen A01175505 Uy Tran A01073093 Answer each of the following questions labeling your answers clearly. Save your work in the Desire2Learn Drop box for Lesson 01 – Review Questions. 1.What is the difference between a database and a table? ●A table, a logical structure that is a collection of Rows and Columns to store the data. Columns are the name of the fields, rows are the actual data. Table is one of the components of a database. ●The database is a structure that is a collection of organized data and specific features (Schema) to access them. It includes tables and metadata which is data about data (attributes’ characteristics and the relationships). 2.What does it mean to say that a database displays both entity integrity and referential integrity? ●Entity integrity describes a protection of primary key in table in which all tuples within a table are uniquely identified based on their primary key. The key’s value must be unique and not a null value because nulls are not only unique but also represent data absence. ●Referential integrity describes consistency of data in which a foreign key’s value referenced by one table has a valid value in another corresponding table or in which the foreign key value is null. The null foreign key value makes it possible not to have a corresponding value (within a table since it is not a primary key) but the referenced requirement on values (another table) that are not null makes it impossible to have an invalid value (its role is a primary key). 3.Why are entity integrity and referential integrity important in a database? Entity integrity is crucial, because each value in a row/column is uniquely identified. That helps retrieving or accessing the data always returns valid results with full accuracy. In other words, data is stored in an organized way without redundancy or duplicated value of one attribute. Referential integrity is essential, because its mechanism ensures the accuracy and consistency of data within a relationship. Relationship is described based on a valid foreign key value from a table referenced by a primary key in another table. Entity integrity is important in a database because they will always have a proper search that will be successful and find a match. Referential is important because it will be able to give non existing foreign key value to a table. Why is this page out of focus?This is a Premium document. Become Premium to read the whole document. Why is this page out of focus?This is a Premium document. Become Premium to read the whole document. What are homonyms in database?To have homonyms at the individual level is to say essentially that a particular uri refers to two different things. It is the equivalent of saying that one Social Security Number refers to two different people (intentionally).
What is database synonym?A synonym is a database object that serves the following purposes: Provides an alternative name for another database object, referred to as the base object, that can exist on a local or remote server.
Why is it important to carefully design a database?Importance of Database Design
To ensure data accuracy, you must design a database that only stores relevant and valuable information. A well-designed database is essential to guarantee information consistency, eliminate redundant data, efficiently execute queries, and improve the database's performance.
What does a database expert mean when's he says that a database displays both entity integrity and referential integrity?Entity integrity in databases is a condition where the rows in all of the tables can be uniquely identified using the primary key of its corresponding table. Referential integrity in databases is a condition in which every reference to an entity instance by another entity instance is valid.
|
What are homonyms and synonyms, and why should they be avoided in database design?
Urheberrechte © © 2024 de.ketajaman Inc.
