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Final

ACS-1803 Study Guide - Final Guide: Query Language, Flat File Database, Cname Record


Department
APPLIED COMPUTER SCIENCE
Course Code
ACS-1803
Professor
Eugene Kaluzniacky
Study Guide
Final

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ACS 1803 STUDY QUESTIONS 1
THESE ARE THE SAME QUESTIONS I GAVE YOU TO PREPARE FOR THE MID-
TERM TEST IN OCTOBER. BUT, FOR THE FINAL EXAM, STUDY ONLY THE
QUESTIONS BELOW THAT ARE IN BOLD ( ALSO STUDY THE entire SECOND
SET OF QUESTIONS ON MATERIAL AFTER THE MID TERM, THAT WILL BE UP
SHORTLY)
18. What is a character, a field, a record, a file?
Give examples from student data.
The smallest item of data is a character : e.g., A,b,9,%,$,”
But storing just characters alone in a computer won’t do; we need to group them.
A group of characters is a field: The field has a name, a type (how the computer
will represent it internally) and a length. e.g., First Name, Text type, length 15
(incl. blanks). E.g., “John” is an example of this field.
A group of fields. side-by-side, is known as a record . A record needs to have a
layout (structure, or design).
e.g.:
STUDNO SNAME STREET CITY MAJOR CNO CNAME GRADE
Text Text Text Text Text Text Text Text
4 25 25 20 15 4 20 2
Then there is the data record itself, that is, the real world data for one record that
follows this layout
1234 Lam A 491 Castle Wpg Economics 1803 Computers A
A group of records that follow the same layout and that it makes sense to keep
together is known as a file or table.
e.g.,
STUDNO SNAME STREET CITY MAJOR CNO CNAME GRADE
1234 Lam A 491 Castle Wpg Economics 1803 Computers A
9876 Kelly R 22 Miller Cr Wpg Biology 2002 Finance B
4567 Ng J 399 High St Wpg Business 1304 Accounting C
So, in order to store data on disk meaningfully, so that we can get a variety of useful
information out, we see that we must set up our data, at least in a file.
19b.What is a relational database?.
How does a database approach to storing data in a computer improve upon the flat file
approach?
The relational database model is the most common model used in Data Based
Management Systems(DBMS). DBMS is exactly how it sounds, it's a system
that is used to manage data. When purchasing this type of system it can often
be called relational DBMS or just RDBMS. RDBMS is again exactly how it
sounds it's a system that manages related data. In this form of a DBMS, the
entities are viewed in two-dimensional tables. Rows represent the records,
which is a group of fields and the columns represents the different parts to the
records that are stored in the rows. Let's say you have a person's student ID
number and their mailing information, there student ID number would be the row
and the mailing information would be across the top in separate columns for the
different information(e.g. Postal code, address, etc.). When different records

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have columns in common, different tables can be joined together. Now the
RDBMS in actuality is forming a three-dimensional model. We've already
discussed the rows and columns, but in RDBMS the third dimension is a row of
data that is in common with another file. This allows their to be multiple files that
have one input(column) in common with each other linking them. This one
column in common is called a primary key. For example the student ID number
and mailing information could be related to another file that has the student ID
number of those same students, but with their grades. This therefore eliminates
the need to repeat their mailing information for every grade they get. This is
what makes RDBMS so popular, because it can eliminate repetition of data,
which can save time.
20. Explain the basics of the relational data base design. What is a data base
management system (dbms)? Be able to partition data into several tables such that
these tables would together make a relational database. What is a query language?
What is SQL?
For first part see above answer
A Query is a method used to request information from a database.
SQL(Structured Query language) is the most common query language for the
purpose of searching a database by entering various search criteria. Ex. You
might ask the for it to give you the part numbers for any inventory that stocks
exceed 30. Well a query language structures that query and presents the results
of the query to the user.
20b. What is a database management system (dbms)? What does it do? Give an
example of such a dbms.
Database management system, that is, software that ‘manages’ a database
i.e., sets up the container, then the structure (skeleton) for each table, fills each
table structure with data and then produces a variety of output from this data, on
screen or paper, without much programming.Ex. Microsoft Access.
32. Explain the structure and operations of the world wide web.
Web servers dish out web pages which are read and displayed by web
browsers. A web page consists of text, graphics, and hyperlinks that lead to
another page; this is hypertext. Hypertext Markup Language(HTML) is the
language to define web pages. Browsers read HTML and render pages. A
website is a collection of interlinked web pages created by the same author for a
common purpose. It responds to requests over the Internet from browsers
according to the hypertext transfer protocol(http).
34. Identify four types of websites, when it comes to the degree of interactiveness with
the user.
1. Static: collection of static documents created in HTML and tied together with
links.
2. Static with forms: 90% is pure document delivery, but also has fill-in forms to
collect information from the user.
3. Dynamic Data Access: via a Web page, users can search a catalogue or perform
queries on the contents of a database.
4. Web-based software applications: facilitate business processes beyond
providing information; have a business information system on a Web-site, e.g.,
inventory tracking, sales force automation.
35. Outline an overview of a web session
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