Question 1

Variable-length record structures allow different records in the same file to have different lengths.

Accepted Answer

Variable-length record structures are designed to accommodate records of varying sizes, allowing each record in a file to have a different length based on its content.

Question 2

When a computer program "reads" a record from a database, it actually retrieves a group or block (or page.) of records at a time. This approach minimizes the number of actual disk accesses.

Accepted Answer

This is true because reading data in blocks or pages reduces the number of disk accesses, which is more efficient than reading one record at a time due to the high latency of disk operations.

Question 3

A variable-length record structure means that each record instance has the same fields, same number of fields and the same logical size.

Accepted Answer

A variable-length record structure means that each record instance can have different fields, a different number of fields, and different logical sizes.

Question 4

A fixed-length record structure means that each record instance can have different fields, a different number of fields, as long as the length (size) of the record is always fixed at the same size.

Accepted Answer

A fixed-length record structure means that each record has the same number of fields and each field has a fixed size, ensuring that the total size of each record is consistent.

Question 5

A blocking factor is the number of physical records included in a single read or write operation.

Accepted Answer

The answer of A blocking factor is the number of...

Question 6

The set of all occurrences of a given record structure in a database system is frequently called a table.

Accepted Answer

In a database system, a table is a collection of records (or rows) that share the same structure, defined by columns.

Question 7

Master files or tables contain records that are relatively permanent. Thus, once a record has been added to a master file, it remains in the system indefinitely. The values of fields for the record will change over its lifetime, but the individual records are retained indefinitely.

Accepted Answer

Master files or tables are designed to store core data that is essential for the operation of a system, and while the data within the records may be updated, the records themselves are typically retained for long-term reference and use.

Question 8

Transaction files or tables contain records that describe business events. The data describing these events normally has a limited useful lifetime.

Accepted Answer

Transaction data is often time-sensitive and relevant for a specific period, after which it may lose its immediate usefulness for operational purposes.

Question 9

Document files and tables contain stored copies of historical data for easy retrieval and review without the overhead of regenerating the document.

Accepted Answer

Document files and tables are used to store historical data, allowing for easy access and review without needing to recreate the data each time it is needed.

Question 10

Archival files and tables contain master and transaction file records that have been moved from on-line storage to off-line storage.

Accepted Answer

Archival files and tables are used to store data that is not needed for immediate access, moving them from online (active) storage to offline (inactive) storage for long-term retention.

Question 11

Table look-up files contain relatively static data that can be shared by applications to maintain consistency and improve performance.

Accepted Answer

Table look-up files store static data that doesn't change often, allowing multiple applications to access the same data, ensuring consistency and reducing the need for repeated data retrieval operations, thus improving performance.

Question 12

Audit files are special records of updates to other files, especially master and transaction files. They are used in conjunction with archival files to recover "lost" data. Audit trails are typically built into better database technologies.

Accepted Answer

Audit files, or audit trails, track changes and updates to files, helping in data recovery and ensuring data integrity, and are often integrated into advanced database systems.

Question 13

In today's database environment, the database technology itself usually predetermines and/or limits file organization for all tables contained in the database.

Accepted Answer

In most modern database management systems, the database technology itself determines the file organization for all tables in the database. This is because the database technology is responsible for managing the storage and retrieval of data, and the file organization is a key factor in determining how efficiently data can be stored and retrieved.

Question 14

Many information systems shops hesitate to give end users access to operational databases for queries and reports.

Accepted Answer

End users accessing operational databases can lead to performance issues, data integrity risks, and security concerns, which is why many information systems shops are hesitant to allow such access.

Question 15

Data are a resource that must be controlled and managed!

Accepted Answer

Data is considered a valuable asset for organizations, requiring proper management and control to ensure its quality, security, and effective use.

Question 16

Prototyping is an alternative to doing database design.

Accepted Answer

Prototyping is a method used to visualize and test ideas early in the development process, while database design is a structured approach to organizing and structuring data. They serve different purposes and are not alternatives to each other.

Question 17

Once a database design and its corresponding schema have been completed, a prototype database can usually be generated very quickly.

Accepted Answer

A prototype database can be quickly generated once the design and schema are completed because the structure is already defined, allowing for rapid implementation using database management systems.

Question 18

Most modern database management systems (DBMS) include powerful, menu-driven database generators that automatically create a DDL and generate a prototype database from that DDL.

Accepted Answer

Most modern DBMSs offer tools that simplify database creation, including menu-driven interfaces that help generate Data Definition Language (DDL) scripts and prototype databases.

Question 19

The advantages and disadvantages of horizontal versus vertical distribution of data are similar.

Accepted Answer

Horizontal distribution involves storing data in rows, while vertical distribution stores data in columns. Both have advantages and disadvantages, but they are not similar.

Question 20

Centralization of the database refers to the physical distribution of entire tables to multiple locations on central processing units.

Accepted Answer

Centralization of a database refers to storing all data in a single, central location, not distributing it across multiple locations.

Quiz 14: Database Design