Database

Database

Physical Database Design has 30 Questions
If a denormalization situation exists with a one-to-one binary relationship, which of the following is true?

All fields are stored in one relation.
All fields are stored in two relations.
All fields are stored in three relations.
All fields are stored in four relations.
Two basic constructs to link one piece of data with another piece of data: sequential storage and pointers.

True
False
Selecting a data type involves which of the following?

Maximize storage space
Represent most values
Improve data integrity
All of the above.
Denormalization and clustering can work well to minimize data access time for small records.

True
False
What is the best data type definition for Oracle when a field is alphanumeric and has a length that can vary?

VARCHAR2
CHAR
LONG
NUMBER
Hashing algorithm converts a primary key value into a record address.

True
False
If a denormalization situation exists with a many-to-many or associative binary relationship, which of the following is true?

All fields are stored in one relation.
All fields are stored in two relations.
All fields are stored in three relations.
All fields are stored in four relations.
The primary goal of physical database design is data processing efficiency.

True
False
Which of the following is an advantage of partitioning?

Complexity
Inconsistent access speed
Extra space
Security
A bitmap index is an index on columns from two or more tables that come from the same domain of values.

True
False
The blocking factor is:

a group of fields stored in adjacent memory.
the number of physical records per page.
attributes grouped together by the same primary key.
attributes grouped together by the same secondary key.
When storage space is scarce and physical records cannot span pages, creating multiple physical records from one logical relation will minimize wasted storage space.

True
False
Which of the following improves a query's processing time?

Write complex queries.
Combine a table with itself.
Query one query within another.
Use compatible data types.
A field represents each component of a composite attribute.

True
False
Which of the following are integrity controls that a DBMS may support?

Assume a default value in a field unless a user enters a value for that field.
Limit the set of permissible values that a field may assume.
Limit the use of null values in some fields.
All of the above.
Some advantages of partitioning include: efficiency, security, and load balancing.

True
False
Which of the following is not a factor to consider when switching from small to large block size?

The length of all of the fields in a table row.
The number of columns
Block contention
Random row access speed
A pointer is a detailed coding scheme recognized by system software for representing organizational data.

True
False
What is the best data type definition for Oracle when a field is alphanumeric and has a fixed length?

VARCHAR2
CHAR
LONG
NUMBER
Distributing the columns of a table into several separate physical records is known as horizontal partitioning.

True
False
A secondary key is which of the following?

Nonunique key
Primary key
Useful for denormalization decisions
Determines the tablespace required
An extent is a contiguous section of disk storage space.

True
False
The fastest read/write time and most efficient data storage of any disk array type is:

RAID-0.
RAID-1.
RAID-2.
RAID-3.
The three newest database architectures in use today are relational, multidimensional and hierarchical.

True
False
A rule of thumb for choosing indexes for a relational database includes which of the following?

Indexes are more useful on smaller tables.
Indexes are more useful for columns that do not appear frequently in the WHERE clause in queries.
Do not specify a unique index for the primary key of each table.
Be careful indexing attributes that have null values.
Data-volume and frequency-of-use statistics are not critical inputs to the physical database design process.

True
False
Sequential retrieval on a primary key for sequential file storage has which of the following features?

Very fast
Moderately fast
Slow
Impractical
In general, larger block sizes are used for online transaction processing applications and smaller block sizes are used for databases with a decision support or data warehousing system.

True
False
A multidimensional database model is used most often in which of the following models?

Data warehouse
Relational
Hierarchical
Network
It is usually not very important to design the physical database to minimize the time required by users to interact with the information systems.

True
False