Use secure chat rooms; those that don’t permit tracking of your ISP address.

Never use your real name in a chat room.

Choose a chat room nickname that doesn’t offend others.

Be extremely careful when sharing information about yourself online.

Never give out your work e-mail address for personal business. Hackers can find out too much information about you that way: where you work, your real name.

Avoid getting into arguments online, a.k.a. flame wars. Stalkers or harassers love to pick an opposing view just to irritate others; don’t fall for their childish behavior— stop arguing or leave the chat room.

Remember, people who use the Internet are strangers. Treat them as you would a stranger you meet on the street: courteous, yet careful.

Get out of a conversation with someone online who has become hostile or sexual. Log off or go to another chat room.

Don’t flirt online. In the real world, flirting or making sexual advances toward someone you don’t know or have never seen is risky; the cyberworld is no different.

Strangers can gain access to e-mail addresses by looking through instant messaging directories that are listed by mail providers. Yahoo, America Online, and Microsoft Network all have directories. To avoid being listed in any of the directories, refer to your e-mail provider’s security section to find out how to eliminate your name from their lists, and follow these precautionary measures:

• Sign up for mail anonymously.
• Never use your real name.
• Don’t put any information in the “user profile” section. If it is required, be extremely general.
• Do not accept messages from anyone who is not on your “friends” list.
• Don’t accept messages that are sent to multiple recipients.
• Disable the “Web aware” feature. No one needs to know when you are on- or offline.
• If you get messages from people you do not want to hear from, put them on the “ignore” list.

What to Do if You Are Being Cyberstalked

These are a few recommendations if you find yourself a possible victim of harassment or stalking on the Internet:

• Save all evidence.
• File a report with local law enforcement.
• Report the incident to your ISP. Contact the system administrator and find out about their abuse policy.
• Report the incident to the ISP of the harasser or stalker if you know it.
• File a report with your appropriate ISP channel: Abuse@yahoo.com or postmaster@yahoo.com.
• Change your screen name.
• Change your password.

The laws against cyberstalking differ from state to state. Because of the newness of the Internet, cyberstalking, like stalking, is a relatively new subject to law enforcement. The laws against the crime of stalking have advanced quite a bit in the last ten years. If you are a victim of cyberstalking, check with local police to find out how the laws read in your state. For more direct help, contact a victims’ advocate Web site, like www.wiredpatrol.org or www.wiredkids.org. They can assist you in filing a report and help you with any questions you might have.

According to emailabuse.com, there are several things you can do to avoid becoming a victim of e-mail abuse. So far, there are no foolproof measures, but following these suggestions can greatly reduce your risk.

If you have any doubts as to the authenticity of the sender and/or the content, do not respond to it. They may sell your address to every spammer out there. Instead, contact the service provider directly in hope of getting the offender’s service terminated.

Report Internet fraud to the Federal Trade Commission or the National Consumer Complaint Center.

Get a free e-mail account somewhere online specifically for newsgroups and when registering on Web sites. Most spammers use programs to gather addresses from these sources. The spammers will get this address and all the junk email will flood this mailbox instead of your working one.

Don’t post your actual e-mail address on your Web site. Again, spammers have programs that can scan your pages for your address.

Use mail filters. They are not always completely accurate, but they can cut back on the number of junk e-mails you receive.

Beware of Viruses

Another danger of opening unsolicited mail is the possibility being attacked by a virus. These can quickly destroy valuable data and leave devastating damage in their wake. What’s more annoying than getting a virus from someone you know because they opened something they shouldn’t have, which then infiltrated their address book and passed it on to you? There are software programs that you can install on your computer that protect you from most viruses. The most popular, Norton AntiVirus, works pretty well to keep out most viruses. But remember: Your anti-virus software is only as good as the frequency of your updates. Experts update their software every day. You can do this by programming your software to update your system frequently; for maximum protection this should be done daily.

How to Ward off Viruses

Most viruses are spread through ignorance. According to email abuse.org, the following can help prevent infection.

Do not open attached files, especially .exe files, if you are not positive where they came from. Virus developers use something called “social engineering” that can make a harmful attachment look like it came from your friend Jane, when, in fact, Jane unknowingly has the virus, and it sent itself to everyone in Jane’s mailbox. Another “red flag” are attatchments that have two periods, like myfile.doc.scr; be suspicious if you see them. It’s smart to verify with the sender what they sent before you open the attachment.

CD Run virus scanning software or virus releases. As stated above; Norton AntiVirus or other anti-virus product.

Keep up with current news on virus releases. If you know what’s out there, you can take measures to avoid infection.

Taking steps to stop spamming or reporting e-mail abuse helps every Internet user. The more people who start reporting abuse or quit opening or buying products from spam advertising, the better chance honest users have of putting the bad guys out of business.

E-mail abuse is characterized as the use of electronic mail to harass, annoy, or cause harm to the e-mail recipient. Abuse can take the form of threatening e-mail, or bulk mail with the intent to slow productivity or cause damage to the recipient’s system. This is a worldwide problem; anyone with e-mail is at risk.

Many people link the term spam to this abuse. While spamming is quite annoying, not all spam mail is linked to criminal activity.

A Word about Spam

According to spamabuse.org, “the term Spam is to flood the Internet with many copies of the same message in an attempt to force the message on people who would not otherwise choose to receive it. Most spam is commercial advertising, often for dubious products: get-rich-quick schemes or quasi-legal services. Spam costs the senders very little—most of the costs are paid by the recipient or the carriers rather than the sender.”

Spam with a Criminal Twist

Regardless of the ethics of spam mail, the criminal aspect arises when a spammer’s sole purpose is to go information fishing. One of the first things my cyberguru John Flowers warned me about was the fraudulent side of spamming. There are deviants who set up a spamming business for the purpose of snagging valid e-mail addresses to gain access to your personal profile. After accumulating your personal information, these trollers then sell all the information to anyone who will pay for it—potentially including pedophiles, stalkers, or identity thieves.

Investigate Yourself

To find out what kind of personal information is already out there about you, search the Web yourself. Go to sites like switchboard.com or dogpile.com. They offer various types of searches on people for a fee, depending how in-depth you want to get.

Whatever You Do . . . Don’t Click the Box

Most spam mail that you receive will have a “take me off your list” box for you to check. What is disguised as a courteous service is really a trap. One click in the box tells them you are a valid e-mail address and you’ll get even more junk mail. According to Kaitlin Duck Sherwood, author of the Overcome E-Mail Overload series of guides, “If you have an ISP with millions of users, like America Online, and you have a user name made up of English words or a common name, spammers will guess it.” So remember, don’t click the box—hit DELETE instead.

Use a Filter to Sift through the Problem

An easy way to cut down on unwanted e-mails or unwanted solicitations is to set filters that come with your e-mail software. Refer to an anti-spam Web site to learn how to recognize characteristics that most spam mail contains, and set your filters accordingly. If you really want to get serious, there are more aggressive anti-spam products that you can buy. Programs like SpamEater or SpamBuster use artificial intelligence to figure out what’s spam and what’s not.

to be continued

• Online
• Not Available
• Away

• Do not disturb
• Calls are being forwarded Offline
• Offline with Voice Mail active Pending Authorization
• Each of these icons tells you each Skype user’s status.

Online

Users with the icon are online and available for all features of Skype.

Not Available

Users with the icon have been away from their computer for an extended period of time but are available for all features of Skype.

Away

Users with the icon are away from their computer for a short period of time and avail‑able for all features of Skype.

Do Not Disturb

Users with the icon are announcing that they would prefer not to be contacted.

However this status indicator, in and of itself, does not actually prevent contact from others.

Calls Are Being Forwarded

Users with the icon have Call Forwarding enabled and available for all features of Skype. If you send a file or chat message, the user will not receive it until the next time he or she launches Skype. If you place a voice call to this user, you will reach that user on the telephone or the user to whom they forwarded their account.

Offline

Users with the icon are probably genuinely offline, and this makes them unavailable for all features of Skype, but they may also have made themselves Invisible, in which case they can still be contacted if you try. If a user’s Privacy Setting permits it, and you send a file or chat message when they are actually offline, they will not receive it until the next time they are online, and this may not occur until the next time they launch Skype. If you place a call to this user, Skype will ring them until it is convinced that they are genuinely offline, invisible or until the user answers.

Offline with Voice Mail

Users with the icon are apparently offline as indicated above, and most of the time this means that they are unavailable for all features of Skype. After a preset number of rings (15 by default) you will be directed to his or her voicemail to leave a message.

Pending Authorization

Users with the icon have not yet authorized you and this only means that you cannot yet see their online status. It does not prevent you from contacting them in any way unless they have elevated their Privacy Option from the default setting (which is to allow chats and calls from anyone).

Using Chat or Instant Messaging

Skype has a very nice chat or IM client that allows you to carry on not only one-on-one chats but also multiuser chats. IM or Chat is the most basic of options for Skype, but it will also be the most used, next to the voice call feature, of course.

Setting the Double-Click Option to Start a Chat

The first order of business we recommend is setting your double-click option to Start a Chat. Setting Skype to Start a Chat on double-clicking a contact name will align with what most of us are used to with other IM products, since this is what happens when you double-click a username in MSN, Yahoo!, AIM, and other IM solutions.

• MSN Messenger 178.2 million users worldwide*
• Yahoo! Instant Messenger 78.8 million users worldwide*
• AOL Instant Messenger 30 million users worldwide*
• ICQ 29.2 million users worldwide*
• iChat Only for Apple Mac users; it is compatible with AIM
• n GAIM for Linux
• IRC Internet Relay Chat
• Trillian Supports ICQ, IRC, AIM,Yahoo! and MSN chats
• GoogleTalk The newest player
• Skype 50 million worldwide users as of August 2005; growing by 150,000 users daily

Skype does almost everything these other solutions do as far as instant messaging, but as we stated in the beginning, Skype has voice capability, which takes IM to another level. Skype is clearly the fastest-growing IM application and soon will be in third place in terms of users worldwide, behind Yahoo! Instant Messaging, probably by the end of 2005. With the additions coming to Skype for Video, for example, Skype will soon rival Microsoft MSN Messenger in number of users globally.

You do not have to run just one IM application, of course. Many of us have AIM, MSN,Yahoo! and Skype all running so that we are as connected as we can be, since everyone uses something different and you want to be able to chat with all your contacts on whatever application they have. The nice thing is that all these IM solutions play well with one another and do not cause any issues when running at the same time, so go ahead and fill up your taskbar or dashboard with IM icons.

As a matter of fact, I use Skype with MSN Messenger at the same time with my daughter and family.

First, it uses checkboxes to mark “Required” fields. Users can’t change these checkboxes; they are only indicators. Farther down the form is a text box labeled “Special Instructions.” These are instructions for filling out the form. They are in a text-entry box like the one below it, but are not editable.

Part of the problem is that some GUI toolkits allow controls to be set to “noneditable.” This encourages developers to misuse editable-looking controls to display noneditable data.

Noneditable text fields

Text fields are the input controls most commonly misused for presenting noneditable data. An example occurs in Microsoft Windows’ Regional and Language preferences window.

Reasons for the blooper

GUI developers typically commit this blooper for one of several different reasons:

1. Setting editability but not appearance. Input controls in most GUI toolkits have an attribute that controls their editability. Unfortunately, many toolkits do not automatically change the appearance of noneditable controls: they continue to look editable unless programmers explicitly set appearance attributes, such as border visibility or interior background color. Predictably, programmers often set a control to noneditable and don’t change its appearance attributes. The result is this blooper.

2. The GUI toolkit let me do it, so it must be OK. Many programmers don’t know the guidelines (because they haven’t seen any) and assume that if a GUI toolkit lets them do something, it must be OK. Bad assumption!

3. But I made it inactive. Most GUI toolkits allow controls to be set to inactive: they don’t respond to user actions until they are again set to active. Inactive controls look grayed-out. However, noneditable data is different from inactive input control and should look different. When GUI toolkits do provide both an active/inactive attribute and an editability attribute on controls, some programmers don’t know which one to use and use the wrong one.

4. Labels are only for labels, right? The fourth reason comes from misleading control names. Most GUI toolkits have a control for displaying noneditable text on a panel. Alas, many toolkits call this a “label.” This suggests that the control should be used only for text that labels something. That, in turn, suggests that text that doesn’t function as a label, such as read-only data, should be displayed using another control. The only other candidate for displaying text is a noneditable text field. Hence, the blooper. In some GUI toolkits, noneditable text controls have better names: “text item,” “static text,” or “text.”

5. It has to look the same as the editable screen. Applications may display the same data in several places, but it is editable in only some places. In such cases, developers sometimes display all of the values as text fields for “consistency.” This is consistency from a developer’s point of view. To users it is inconsistent.

6. It is user-editable—just not directly. Perhaps users can edit the data, but only by bringing up an Edit window, not by clicking and typing in the field itself.

7. The data varies. The final reason for noneditable data in editable- looking controls is that the data in the controls varies. The uBid.com “Email Us” page is used for several purposes: requesting Customer Support, reporting Web site problems, etc. The required fields and special instructions vary between different uses of the form. Because of this, the designers of this page probably felt it was OK to use non-user-editable checkboxes for marking required fields and a nonuser-editable text area for containing the special instructions. Wrong! Just because the data varies does not excuse the use of controls that mislead users.

First, it uses checkboxes to mark “Required” fields. Users can’t change these checkboxes; they are only indicators. Farther down the form is a text box labeled “Special Instructions.” These are instructions for filling out the form. They are in a text-entry box like the one below it, but are not editable.

Part of the problem is that some GUI toolkits allow controls to be set to “noneditable.” This encourages developers to misuse editable-looking controls to display noneditable data.

Noneditable text fields

Text fields are the input controls most commonly misused for presenting noneditable data. An example occurs in Microsoft Windows’ Regional and Language preferences window.

Reasons for the blooper

GUI developers typically commit this blooper for one of several different reasons:

1. Setting editability but not appearance. Input controls in most GUI toolkits have an attribute that controls their editability. Unfortunately, many toolkits do not automatically change the appearance of noneditable controls: they continue to look editable unless programmers explicitly set appearance attributes, such as border visibility or interior background color. Predictably, programmers often set a control to noneditable and don’t change its appearance attributes. The result is this blooper.

2. The GUI toolkit let me do it, so it must be OK. Many programmers don’t know the guidelines (because they haven’t seen any) and assume that if a GUI toolkit lets them do something, it must be OK. Bad assumption!

3. But I made it inactive. Most GUI toolkits allow controls to be set to inactive: they don’t respond to user actions until they are again set to active. Inactive controls look grayed-out. However, noneditable data is different from inactive input control and should look different. When GUI toolkits do provide both an active/inactive attribute and an editability attribute on controls, some programmers don’t know which one to use and use the wrong one.

4. Labels are only for labels, right? The fourth reason comes from misleading control names. Most GUI toolkits have a control for displaying noneditable text on a panel. Alas, many toolkits call this a “label.” This suggests that the control should be used only for text that labels something. That, in turn, suggests that text that doesn’t function as a label, such as read-only data, should be displayed using another control. The only other candidate for displaying text is a noneditable text field. Hence, the blooper. In some GUI toolkits, noneditable text controls have better names: “text item,” “static text,” or “text.”

5. It has to look the same as the editable screen. Applications may display the same data in several places, but it is editable in only some places. In such cases, developers sometimes display all of the values as text fields for “consistency.” This is consistency from a developer’s point of view. To users it is inconsistent.

6. It is user-editable—just not directly. Perhaps users can edit the data, but only by bringing up an Edit window, not by clicking and typing in the field itself.

7. The data varies. The final reason for noneditable data in editable- looking controls is that the data in the controls varies. The uBid.com “Email Us” page is used for several purposes: requesting Customer Support, reporting Web site problems, etc. The required fields and special instructions vary between different uses of the form. Because of this, the designers of this page probably felt it was OK to use non-user-editable checkboxes for marking required fields and a nonuser-editable text area for containing the special instructions. Wrong! Just because the data varies does not excuse the use of controls that mislead users.

Suppose that you wanted to figure the average salary paid to employees according to each city. You would do this by using the aggregate function AVG on the SALARY column, as you learned last hour, and by using the GROUP BY clause to group the output by city.

Grouping data is accomplished through the use of the GROUP BY clause of a SELECT statement (query). Last hour, you learned how to use aggregate functions.

The GROUP BY Clause

The GROUP BY clause is used in collaboration with the SELECT statement to arrange identical data into groups. The GROUP BY clause follows the WHERE clause in a SELECT statement and precedes the ORDER BY clause.

The GROUP BY clause must follow the conditions in the WHERE clause and must precede the ORDER BY clause if one is used.

Grouping Selected Data

Grouping data is a simple process. The selected columns (the column list following the SELECT keyword in a query) are the columns that can be referenced in the GROUP BY clause. If a column is not found in the SELECT statement, it cannot be used in the GROUP BY clause. This is logical if you think about it—how can you group data on a report if the data is not displayed?

If the column name has been qualified, the qualified name must go into the GROUP BY clause. The column name can also be represented by a number. When grouping the data, the order of columns grouped does not have to match the column order in the SELECT clause.

Group Functions

Typical group functions—those that are used with the GROUP BY clause to arrange data in groups—include AVG, MAX, MIN, SUM, and COUNT. These are the aggregate functions that you learned about during Hour 9, “Summarizing Data Results from a Query.” Remember that the aggregate functions were used for single values in Hour 9; now, you use the aggregate functions for group values.

Creating Groups and Using Aggregate Functions

There are conditions that the SELECT clause has that must be met when using GROUP BY. Specifically, whatever columns are selected must appear in the GROUP BY clause, except for any aggregate values. The columns in the GROUP BY clause do not necessarily have to be in the same order as they appear in the SELECT clause. Should the columns in the SELECT clause be qualified, the qualified names of the columns must be used in the GROUP BY clause.

Indexing on a single column of a table is the simplest and most common manifestation of an index. Obviously, a single-column index is one that is created based on only one table column.

Unique Indexes

NEW TERM Unique indexes are used not only for performance, but also for data integrity. A unique index does not allow any duplicate values to be inserted into the table. Otherwise, the unique index performs the same way a regular index performs.

Composite Indexes

A composite index is an index on two or more columns of a table. You should consider performance when creating a composite index because the order of columns in the index has a measurable effect on data retrieval speed. Generally, the most restrictive value should be placed first for optimum performance. However, the columns that will always be specified should be placed first.

Single-Column Versus Composite Indexes

In deciding whether to create a single-column index or a composite index, take into consideration the column(s) that you may use very frequently in a query’s WHERE clause as filter conditions. Should there be only one column used, a single-column index should be the choice. Should there be two or more columns that are frequently used in the WHERE clause as filters, a composite index would be the best choice.

Implicit Indexes

Implicit indexes are indexes that are automatically created by the database server when an object is created. Indexes are automatically created for primary key constraints and unique constraints. Why are indexes automatically created for these constraints? Imagine that you are the database server. A user adds a new product to the database. The product identification is the primary key on the table, which means that it must be a unique value. To efficiently check to make sure the new value is unique among hundreds or thousands of records, the product identifications in the table must be indexed. Therefore, when you create a primary key or unique constraint, an index is automatically created for you.

When Should Indexes Be Considered?

Unique indexes are implicitly used in conjunction with a primary key for the primary key to work. Foreign keys are also excellent candidates for an index because they are often used to join the parent table. Most, if not all, columns used for table joins should be indexed.

Columns that are frequently referenced in the ORDER BY and GROUP BY clauses should be considered for indexes. For example, if you are sorting on an individual’s name, it would be quite beneficial to have an index on the name column. It renders an automatic alphabetical order on every name, thus simplifying the actual sort operation and expediting the output results.

Furthermore, indexes should be created on columns with a high number of unique values, or columns when used as filter conditions in the WHERE clause return a low percentage of rows of data from a table. This is where trial and error may come into play. Just as production code and database structures should always be tested before their implementation into production, so should indexes. This testing is time that should be spent trying different combinations of indexes, no indexes, single-column indexes, and composite indexes. There is no cut-and-dried rule for using indexes. The effective use of indexes requires a thorough knowledge of table relationships, query and transaction requirements, and the data itself.

When Should Indexes Be Avoided?

Although indexes are intended to enhance a database’s performance, there are times when they should be avoided. The following guidelines indicate when the use of an index should be reconsidered:

Indexes should not be used on small tables.

Indexes should not be used on columns that return a high percentage of data rows when used as a filter condition in a query’s WHERE clause. For instance, you would not have an entry for the word “the” or “and” in the index.

Tables that have frequent, large batch update jobs run can be indexed. However, the batch job’s performance is slowed considerably by the index. The conflict of having an index on a table that is frequently loaded or manipulated by a large batch process can be corrected by dropping the index before the batch job, and then recreating the index after the job has completed.

Indexes should not be used on columns that contain a high number of NULL values.

Columns that are frequently manipulated should not be indexed. Maintenance on the index can become excessive.