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Basic Defns
More of the First
ERD Rules!
ERD Rocks!
Relational Model Surges!
100
Stores information in the form of logically related two-dimensional tables
What is a relational database?
100
a person, place, thing, transaction, or event about which information is stored.
What is an entity?
100
An attribute that can be and must be broken into smaller/simpler attributes.
What is a composite attribute?
100
In problem 10 on inclass exercises, department is this.
What is an entity?
100
For the ERD for problem 10, the 1-M Employs relationship will be handled in a relational model like this.
What is "create DEPTNAME as a foreign key column in Employee"?
200
a field (or group of fields) that uniquely identifies a given record in a table
What is a primary key?
200
Characteristics or properties of an entity class that you give a name or label to.
What is an attribute?
200
Am attribute that can be calculated from other attributes.
What is a derived attribute?
200
To capture department head, we must do this.
What is create a relationship between employee and department called "headed by"? Dept - Employee M -1.
200
To account for the "Headed By M-1" relationship between Department and Employee, we must do this in a relational model.
What is "create a foreign key called DeptHeadEmpNo in Department as referencing EMPLID in Employee"?
300
A primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables
What is a foreign key?
300
Maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)
What is a database?
300
A "plural" attribute.
What is a multi-valued attribute?
300
To account for employee skills, we must do this.
What is create a new entity called SKILL with attributes SKILLID (pk) and SkillDescription? Employee-Skill M-M.
300
To account for the "is the boss of" unary relationship between Employee to itself, you must do this.
What is "BossEmpID as a foreign key in Employee referencing EMPLID in Employee"?
400
It is a way to abstract organizational data into a conceptual diagram.
What is an entity relationship diagram (ERD)?
400
This is a problem with using LastName of a customer as a primary key.
What is NOT UNIQUE?
400
This is what would result if we have any number of telephone numbers for each customer.
What is a new entity called TelephoneNumber with an attribute TelNumber with one to many relationship with a customer entity.
400
To capture the information that department undertakes a project, we must do this.
What is "create a relationship between department and project entities"? Department - Project 1-M.
400
To account for the M-M relationship "Works On," one must do this.
What is "create a new entity called ProjectEmployeeAssign with ProjectID and EmplID as the primary key, and each as a foreign key referencing the project and employee table primary keys respectively"?
500
You must avoid this when setting up attributes across entities
What is redundancy (duplication) of attributes?
500
This is a problem with using EmployeeStartDate as a primary key in an Employee entity.
What is COULD BE NULL and COULD BE DUPLICATE?
500
To correct the mistake when a student creates an entity student and an entity LastName with 1-1 relationship with each other, you would do this.
What is make LastName an attribute of Student?
500
To capture the information that each project has a project coordinator, we must do this.
What is "create a relationship from employee to project with the name COORDINATES"? Employee-Project 1-M.
500
Suppose that we needed to capture the StartDate of each employee on each project. One must do this on the ERD and on the relational model.
What is "draw an associative entity in the ERD from Works On relationship and place EmpProjStartDate as an attribute, and create a table from the associative entity in the relational model"?