DBA Quiz 8

Foreign keys cannot be null when:

It is part of a primary key

A table does not have to have a primary key

True

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

The explanation below defines which constraint type: A column must contain only values consistent with the defined data format of the column

Column integrity

Column integrity refers to

Columns always containing values consistent with the defined data format

The explanation below defines which constraint type:A primary key must be unique, and no part of the primary key can be null.

Entity integrity

A foreign key always refers to a primary key in the same table.

False

One or more columns in a primary key can be null.

False

One-to-One relationships are transformed into Foreign Keys in the tables created at either end of that relationship? True or False?

False

Relationships on an ERD can only be transformed into UIDs in the physical model? True or False?

False

In a physical data model, a relationship is represented as a:

Foreign Key

What do you create when you transform a many to many relationship from your ER diagram into a physical design?

Intersection Table

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)

Make all relationships optional Create an additional check constraint to verify that one foreign key is populated and the others are not

The explanation below is an example of what 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

Why would this table name NOT work in an Oracle database? 2007_EMPLOYEES

Table names must start with an alphabetic character

The transformation from an ER diagram to a physical design involves changing terminology. Entities in the ER diagram become __________ , and attributes become ____________.

Tables, Columns

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 BS

Attributes become columns in a database table.

True

The explanation below is an example of what 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

Which of the following are reasons you should consider when using a Subtype Implementation? (Choose Two)

When the common access paths for the subtypes are different. Most of the relationships are at the subtype level

A barred Relationship will result in a Foreign Key column that also is part of:

The Primary Key

Identify all of the correct statements that complete this sentence: A primary key is ...(Choose Three)

A single column that uniquely identifies each row in a table A set of columns 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

The transformation from an ER diagram to a physical design involves changing terminology. Relationships in the ER diagram become __________ , and primary unique identifiers become ____________.

Foreign keys, primary keys

One-to-Many Optional to Mandatory becomes a _______________ on the Master table.

Nothing (There are no new columns created on the Master table)