Database Systems (chapter 1) – Answer the questions below thoroughly and completely (one sentence answers will not be sufficient). Submit the assignment as one word document via BlackBoard assignments. Be sure to include your name, course.section and assignment #. Documents without a name or in other formats will not be accepted!
ITEC 315, 851
- Define and explain the difference between data and information?
Data: are raw unorganized facts that have little meaning; an example of a data would be a student’s score on a test.
Information: Are the processing and organization of raw data to reveal meaning; an example of information would be the class test score average, which is collected, processed and organized from each student to produce a meaningful output.
- Define each of the following terms: field, record and file
- Field: A character or group of characters (alphabetic or numeric) that has a specific meaning. A field is used to define and store data.
- Record: A logically connected set of one or more fields that describe a person, place, or thing. For example, the fields that constitute a record for a customer might consist of the customer’s name, address, phone number, date of birth, credit limit, and unpaid balance.
- File: A collection of related records
- What is a database? What is a DBMS and what are its functions?
A database is a shared, integrated computer structure that stores a collection of: raw facts of interest to end user “end-user data”, and data about data “Metadata”
A database can be classified according to: number of users, database location(s), and expected type and extent of use.
DBMS: is a collection of programs that manage the database structure and that control shared access to the data in the database.
The functions of a DBMS are as follow:
- Data dictionary management:
DBMS stores definitions of data elements and relationships (metadata) in a data dictionary.
- Data storage management:
DBMS creates and manages complex structures required for data storage.
- Data transformation and presentation:
DBMS transforms data entered to conform to required data structures.
- Security management:
DBMS creates a security system that enforces user security and data privacy.
- Multiuser access control:
DBMS uses sophisticated algorithms to ensure concurrent access does not affect integrity.
- Backup and recovery management:
DBMS provides backup and data recovery to ensure data safety and integrity.
- Data integrity management:
DBMS promotes and enforces integrity rules to minimize redundancy and maximize consistency.
- DBMS provides access to the data via utility programs and from programming languages interfaces.
- DBMS provides end-user access to data within a computer network environment.
- What is data redundancy, and which characteristics of the file system can lead to it?
Data redundancy referenced to same data stored unnecessarily in different places. It can lead to poor data security, as having multiple copies of data increase the chance of a copy of the data to be susceptible to unauthorized access. It can also lead to data inconsistency, where data exist when different and conflicting versions of the same data appear in different places. For example, suppose you change an agent’s phone number or address in the AGENT file.
- Use examples to compare and contrast unstructured and structured data. Which type is more prevalent in a typical business environment?
Unstructured data are data that exist in their original raw state.
Structured data result from formatting structure applied based on type of processing to be performed. An invoice would be an example for both types. If I take an invoice and scan it into a graphic format, it would be unstructured data. But if it were processed and put into a database (subsequently becoming structured data), I could eventually find the monthly averages, amount owed, etc.
- How many records does the file contain? How many fields are there per record?
The file contains seven records which are 21-5Z through 31-7P.
There are five fields per record which are PROJECT_CODE through PROJECT_BID_PRICE.
- What problem would you encounter if you wanted to produce a listing by city? How would you solve this problem by altering the file structure?
The city names are within the MANAGER_ADDRESS attribute, which is the problem that I will face, because queries become much more difficult to write and take longer to execute when internal string searches must be conducted. To solve this it is best to store the city name as a separate attribute.
- If you wanted to produce a listing of the file contents by last name, area code, city, state, or zip code, how would you alter the file structure?
The more we divide things into its component parts, the greater its information capabilities. For example if we divide MANAGER_ADDRESS into its component parts (STREET, CITY, ZIP, and STATE) we have the ability to easily select records on the basis of zip codes, city names, and states, and we also gain more efficient searches and listings.
- What data redundancies do you detect? How could those redundancies lead to anomalies?
The manager named Holly B. Parker occurs three times, which means she is managing three projects (1:M relationship); her address and phone number also occur three times which means if she changes any of her information the change must occur more than once, and done correctly.