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.