Database Section 3 Quiz
Would it be a good idea to model age as an attribute of STUDENT?
No - it is a volatile attribute
Which of the following is true about subtypes?
Subtypes must be mutually exclusive.
When converting attribute names to columns __________ are frequently used.
abbreviations
How many subtypes can a supertype have?
any number
A ___________ relationship is created when the UID for an entity includes the relationship with another entity.
barred
Intersection Entities often have the relationships participating in the UID, so the relationships are often barred. (true/false)
true
Modeling historical data can produce a unique identifier that includes dates. (true/false)
true
Modeling historical data is optional.
true
Normalizing an Entity to 1st Normal Form is done by removing any attributes that contain multiple values. (true/false)
true
The Rule of 3rd Normal Form states that No Non-UID attribute can be dependent on another non-UID attribute. (true/false)
true
We take the primary key from the "one" table and place it on the "many" table to create a foreign key. (true/false)
true
When mapping a barred relationship, a primary key and foreign key can be the same field. (true/false)
true
A table is in 2NF if A. It meets the requirements for the 1 NF. B. Each non-key attribute is fully functional dependent on the table's primary key. C. Both A and B must be true. D. Neither A or B must be true.
Both A and B must be true.
A recursive relationship has cardinality of ___________.
Cannot be determined without more information.
Which of the following would be a logical constraint when modeling time for a City entity? -Cites may change their names and/or country association if the borders of a country change. -People are born in the city and people die in the city. -If you are doing a system for any French City, you would need security clearance. -Daily traffic patterns must be monitored to determine how many law enforcement officers are needed.
Cites may change their names and/or country association if the borders of a country change.
An entity without repeated values is said to be in __________.
1st normal form
Which of the following scenarios should be modeled so that historical data is kept? (Choose two) (Choose all correct answers) -BABY and AGE -TEACHER and AGE -CUSTOMER and ORDERS -CUSTOMER and PAYMENTS
-CUSTOMER and ORDERS -CUSTOMER and PAYMENTS
In a physical data model, an attribute is represented as a/an
column
Arcs are used to visually represent _________ between two or more relationships in an ERD.
exclusivity
You can only create relationships to a Supertype, not to a Subtype. (true/false)
false
A ______________ is frequently used to track information about a relationship that changes over time.
intersection entity
A recursive relationship _____ mandatory at both ends.
may be
All instances of the supertype _____ be an instance of one of the subtypes.
must
As a database designer, you do not need to worry about where in the datamodel you store a particular attribute; as long as you get it onto the ERD, your job is done. (true/false)
normalization
When data is only stored in one place in a database, the database conforms to the rules of ___________.
normalization
When mapping entities containing super types and subtypes a _________ table implementation is used when most of the attributes and relationships are shared at the super type level.
single-table
Table names can contain all of the following except:
spaces
A new system would have a mixture of both Procedural and Structural Business Rules as part of the documentation of that new system. (true/false)
true
If there is a column missing in an entity - normalization should identify this problem. (true/false)
true
