Notes, summaries, assignments, exams, and problems for Computers

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Relational Database Concepts: Keys, Views, and SQL

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Relational Keys

Superkey: Set of attributes with all those needed to ID a particular row. Candidate key: Minimal superkey; removing any attribute means it is no longer a superkey; can be multiple per relation; "UNIQUE". Strict: Candidate key + at least 1 extra attribute. Primary: Default candidate key, reference for foreign keys; automatically unique; "PRIMARY KEY". Foreign: "Logical pointer" in a dependent relation that refers to the candidate key in the parent relation (not always primary). Natural: Represent conceptual uniqueness constraints external to the DB, e.g., name, address. Artificial: Introduced solely for the DB, no external meaning, e.g., auto-generated ID; single attribute, simple data type. Surrogate: If artificial is used as
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OSI Model and TCP/IP: Understanding Network Layers

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The Open Systems Interconnection Model

The Open Systems Interconnection (OSI) model is an abstract, layered representation created as a reference for network protocol design. The OSI model divides the process of networking into different logical layers, each of which has unique functionality and to which specific services and protocols are assigned.

Application Layer

The application layer, the seventh layer, is the top layer of both the OSI and TCP/IP models.

Presentation Layer

The presentation layer has three main functions:

  • Coding and data conversion of the application layer to ensure that data from the source device can be interpreted by the appropriate application on the target device.
  • Compression of the data in a way that can be decompressed
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Adobe Fireworks CS4: Features and Capabilities

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Adobe Fireworks CS4: A Powerful Tool for Web Graphics

Fireworks was originally created in 1998 by Macromedia. Since the company was acquired by Adobe Systems Incorporated, it has been part of the Adobe family. The most recent and improved version is Fireworks CS4.

Fireworks is a software from the multimedia family, and it is a versatile application. Images for the web can be created, designed, edited, and optimized easily. The use of this software is not exclusive to people who work in this area. Those who enjoy design and creating their own images or editing their favorite pictures can use the program. Company logos, advertising banners, and even animations are developed with it. This way, web pages become more attractive and receive more visits.

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Adobe Fireworks: Interface and Tools Explained

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Understanding the Adobe Fireworks Interface

Before getting started, let's define Object as any element within Fireworks, such as a circle, line, picture, or text.

The Fireworks Interface is simple. It's essential to identify each element, as you'll be using them throughout this course.

Start Page

Upon launching Fireworks, and before opening any document, the Start page appears. Here, you can open an existing document, create a new one, access recent documents, or visit Fireworks Exchange to enhance certain Fireworks functions.

Workspace

Workspace refers to the arrangement of elements like the Tools panel, Property Inspector, menus, and windows. The following image illustrates its layout.

Title Bar or Application Bar

Located at the top, it displays

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Importing Bitmap Images into Fireworks: Supported Formats

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Importing Bitmap Images into Fireworks

Defining the Canvas

The first step is defining the work area or canvas (remember to have the negative area visible). Then, select the import option from the File menu.

A window like the one below will open.

Locating and Selecting the Image

In the Look in option, you'll search the folder where your image is saved. In the Files of type menu, the formats that Fireworks recognizes are shown. Once you select the file, click Open.

Placing the Image

The following mark will be displayed on the canvas, which means Fireworks is ready to bring in the selected image.

Simply click with your mouse or try to trace the desired size of the image.

That way, the image will appear on the canvas.

Image Properties

This image's properties... Continue reading "Importing Bitmap Images into Fireworks: Supported Formats" »

Pascal Code Examples: Arrays, Matrices, and Logic

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Pascal Code Examples

1. String Search in Array

This program searches for a given name within an array of strings.

Program Pzim;
var
  vet1: array[1..10] of string;
  nome: string;
  i, j: integer;
begin
  j := 0;
  for i := 1 to 10 do
  begin
    write('Enter the names: ');
    readln(vet1[i]);
  end;
  write('Enter the name to be searched: ');
  readln(nome);
  for i := 1 to 10 do
  begin
    if (nome = vet1[i]) then
    begin
      writeln('FOUND');
      j := j + 1;
    end;
  end;
  if (j = 0) then
    writeln('NOT FOUND');
end.

2. Merging Two Arrays

This program merges two arrays (vet1 and vet2) into a third array (vetx).

Program Pzim;
var
  vet1: array[1..5] of integer;
  vet2: array[1..10] of integer;
  vetx: array[1..15] of integer;
... Continue reading "Pascal Code Examples: Arrays, Matrices, and Logic" »

Understanding Interrupts in Computer Systems

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a) Advantage of Interrupts for Peripheral Devices

Explain the advantage of using interrupts as a technique for handling peripheral devices and relate it to computer performance. (10)

Answer

Interrupts offer a significant advantage because the processor doesn't need to constantly poll peripherals to check for data readiness. Instead, the peripheral alerts the processor when it's ready. This allows the processor to focus on other tasks while waiting for the peripheral, thus increasing overall computer performance.

b) Multiple Choice Questions on Interrupts

With regard to interrupts, check only what is correct in the following statements. (8) Explain why the last statement has been marked as correct. (7) Total 15 points

1.

To be considered an interrupt,... Continue reading "Understanding Interrupts in Computer Systems" »

Windows Control Panel: System Configuration & Management

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The Windows Control Panel: Your System's Command Center

The Windows Control Panel is your primary tool for configuring both the software and hardware installed on your computer. It organizes utilities into categories for easy access. Here's a breakdown of some key configuration options:

Add Hardware Wizard

This wizard guides you through installing new devices. Typically, you'll need the installation CD provided by the device manufacturer.

Add/Remove Programs (Programs and Features)

This section displays all programs installed on your computer. Select a program to uninstall it. To install a new program, run the installer file. To add or remove Windows features, click on "Turn Windows features on or off."

Network Connections (Network and Sharing Center)

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Image Optimization and Exporting for Web Use

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Image Optimization Process

During image design and transformation, there's complete freedom. Optimization is applied at the end, before exporting the image to a web-compatible format.

Optimization involves three key steps:

  1. Selecting the best file format to manage file size.
  2. Adjusting format options and colors. Each format has specific compression controls, some limiting color palettes.
  3. Defining export options based on image use.

Common Export Formats

  • GIF (Graphics Interchange Format): Up to 256 colors, supports transparency, ideal for animations, logos, and images with transparent areas. Often used for vector graphics.
  • JPEG (Joint Photographic Experts Group): Best for photos and textured images, supports many colors, but has fewer image quality options.
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Working with Databases in Access: A Comprehensive Guide

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Topic 8: Exporting Data from Access

Exportable File Formats

  • SharePoint
  • Word files
  • Excel documents
  • Other Access databases
  • Text files

Linked Tables and Data Updates

Changes made to the original Excel data will not be reflected in the linked Access table.

Dividing a Database

An Access database can be split into two files:

  • Server File: Contains the tables.
  • Client File: Contains forms, reports, and other created objects.

Topic 9: Working with Forms in Access

Simple Forms

Access can automatically generate simple forms from active tables, displaying records in an organized layout and allowing for new data entry.

Form Tools

Form tools simplify the creation of forms by allowing you to select the desired data fields.

Split Forms

Split forms offer two views:

  • Form View
  • Datasheet
... Continue reading "Working with Databases in Access: A Comprehensive Guide" »