Oracle chapter 9
The "Arc Implementation" is a synonym for what type of implementation?
Supertype and Subtype Implementation
A table does not have to have a primary key.
True
Identify all of the correct statements that complete this sentence: A primary key is: (Choose Three)
A set of columns that uniquely identifies each row in a table A single column that uniquely identifies each row in a table A set of columns and keys in a single table that uniquely identifies each row in a single table
Which of the following is a valid reason for considering a Subtype Implementation?
Business functionality, business rules, access paths, and frequency of access are all very different between the subtypes.
In a physical data model, an attribute becomes a _____________.
Column
Column integrity refers to
Columns always containing values consistent with the defined data format
A foreign key cannot refer to a primary key in the same table.
False
In a physical data model, a relationship is represented as a:
Foreign Key
In a physical data model, a relationship is represented as a combination of: (Choose Two)
Foreign Key Primary Key or Unique Key
One-to-Many Optional to Mandatory becomes a _______________ on the Master table.
Mandatory Foreign Key
The explanation below is an example of which constraint type? The value in the dept_no column of the EMPLOYEES table must match a value in the dept_no column in the DEPARTMENTS table.
Referential integrity
In a physical data model, an entity becomes a _____________.
Table
In an Oracle database, why would the following table name not be allowed 'EMPLOYEE JOBS'?
You cannot have spaces between words in a table name
When translating an arc relationship to a physical design, you must turn the arc relationships into foreign keys. What additional step must you take with the created foreign keys to ensure the exclusivity principle of arc relationships? (Assume that you are implementing an Exclusive Design) (Choose Two)
Create an additional check constraint to verify that one foreign key is populated and the others are not Make all relationships optional
The explanation below is an example of which constraint type? A primary key must be unique, and no part of the primary key can be null.
Entity integrity
An "Arc Implementation" can be done just like any other Relationship - you simply add the required Foreign Keys.
False
It is possible to implement non-transferability via a simple Foreign Key Relationship.
False
One-to-One relationships are transformed into Check Constraints in the tables created at either end of that relationship.
False
One-to-One relationships are transformed into Foreign Keys in the tables created at either end of that relationship.
False
Relationships on an ERD can only be transformed into UIDs in the physical model?
False
When an Arc is transformed to the physical model every relationship in the Arc becomes a mandatory Foreign Key.
False
When mapping supertypes, relationships at the supertype level transform as usual. Relationships at subtype level are implemented as foreign keys, but the foreign key columns all become mandatory.
False
In a physical model, many to many relationships are resolved via a structure called a(n): ________________
Intersection Table
The transformation from an ER diagram to a physical design involves changing terminology. Entities in the ER diagram become __________ :
Tables
Two entities A and B have an optional (A) to Mandatory (B) One-to-One relationship. When they are transformed, the Foreign Key(s) is placed on:
The table B
An Arc is transformed to the physical model by adding a foeign Key for every relationship in the Arc.
True
Attributes become columns in a database table.
True
When mapping supertypes, relationships at the supertype level transform as usual. Relationships at the subtype level are implemented as foreign keys, but the foreign key columns all become optional.
True
The explanation below is an example of which constraint type? If the value in the balance column of the ACCOUNTS table is below 100, we must send a letter to the account owner which will require extra programming to enforce.
User-defined integrity
Why would this table name NOT work in an Oracle database? this_year_end+next_year
The Plus sign + is not allowed in object names.
A barrred Relationship will result in a Foreign Key column that also is part of:
The Primary Key
Identify all of the incorrect statements that complete this sentence: A primary key is...(Choose three)
Only one column that must be null. A single column that uniquely identifies each column in a table. A set of columns in one table that uniquely identifies each row in another table.
