Data Integrity

Author : uCertify

The SQL Server 2000 database include datatypes, NOT NULL definitions, DEFAULT definitions, IDENTITY properties, rules, constraints, triggers, and indexes.Enforcing data integrity ensures the quality of data in a database. For example, if a product is entered with a Product_ID value of 25 in a table named Products, the database should not allow another product to have an ID with the same value. Furthermore, if there is a column named Product_Rating that is intended to have values ranging from 1 to 10, the database should not accept a value below 1 and above 10 for this column. This can be accomplished by using the methods supported by SQL Server to enforce the integrity of the data.SQL Server supports a number of methods that can be used to enforce data integrity. These methods include defining datatypes, NOT NULL definitions, DEFAULT definitions, IDENTITY properties, rules, constraints, triggers, and indexes.DatatypesA datatype is an attribute that specifies the type of data (e.g., character, integer, binary, etc.) that can be stored in a column, parameter, or variable. SQL Server provides a set of system-supplied datatypes. However, users can also create user-defined datatypes based on the system-supplied datatypes. System-supplied datatypes define all of the types of data that can be used with SQL Server. Datatypes can be used to enforce data integrity because the data entered or modified must conform to the type specified for the object. For example, a name cannot be stored in a column defined with the datetime datatype, as a datetime column can accept only date values.NOT NULL DefinitionsThe nullability of a table column determines whether the rows in the table can contain a null value for that column. A null value in a column does not mean that the column has zero, blank, or a zero-length character string such as " ". Null in a column means that no data has been entered in that column. The presence of a null in a column implies that the value is either unknown or undefined.The nullability of a column is defined while defining the column or while creating or modifying a table. The NULL keyword is used to specify that the column will allow null values. The NOT NULL keyword specifies that null values will not be allowed in the column. DEFAULT DefinitionsEach column in a row must contain a value even if that value is null. However, certain situations exist when a row is inserted in a table, but the value for a column is not known or the value does not yet exist. If the column allows null values, a row with a null value for that column can be inserted in the table. In some cases, nullable columns might not be desirable. In these cases, a DEFAULT definition can be defined for the column. Defaults specify what values are automatically inserted in a column if a value is not specified for the column when inserting a row in the table. For example, it is common to specify zero as the default for numeric columns and N/A as the default for string columns.When a row is inserted in a table with a default definition for a column, the SQL Server is implicitly instructed to insert the specified default value in the column if a value is not specified for the column.IDENTITY PropertiesThe IDENTITY property is used to define a column as an identifier column. An identifier column contains system-generated sequential values that uniquely identify each row in the table. A table can have only one identifier column. Identifier columns usually contain values that are unique only within the table for which they have been defined. In other words, other tables containing identifier columns can contain the same identity values used by another table. However, the identifier values are typically used only within the context of a single table, and the identifier columns do not relate to other identifier columns in other tables.ConstraintsConstraints are used to define the way that SQL Server automatically enforces the integrity of a database. A constraint is a property assigned to a table or column within a table that prevents invalid data values from being entered in the specified column(s). For example, a PRIMARY KEY or UNIQUE constraint on a column prevents a duplicate value from being inserted into the column. A CHECK constraint on a column prevents the column from accepting a value that does not meet the specified condition. Moreover, a FOREIGN KEY constraint establishes a link between data in two tables.RulesRules perform some of the same functions as CHECK constraints. However, CHECK constraints are preferred over rules. Rules are provided only for backward compatibility. CHECK constraints are more concise than rules. A column can have only one rule applied to it. However, multiple CHECK constraints can be applied to a column. CHECK constraints are specified while creating a table, whereas rules are created as separate objects and are bound to the column.The CREATE RULE statement is used to create a rule. Once a rule has been created, it can be bound to a column or a user-defined data type by using the sp_bindrule system stored procedure.TriggersTriggers are special types of stored procedures that are defined to execute automatically when an UPDATE, INSERT, or DELETE statement is issued against a table or view. Triggers can be used to enforce business rules automatically when data is modified. Triggers can also be used to extend the integrity checking logic of constraints, defaults, and rules. However, it is recommended that constraints and defaults be used instead of triggers whenever they provide all of the needed functionality.IndexesAn index is a database object that orders the values of one or more columns in a table. An index provides pointers to the data values stored in specified columns of the table and orders the pointers in the specified order. When rows are requested from an indexed table, the database searches the index to find a particular value and then follows the pointer to the row containing that value.Types of Data IntegritySQL Server supports the following four types of data integrity:1.Entity IntegrityEntity integrity defines a row as a unique entity for a particular table. Entity integrity enforces the integrity of the identifier column(s) or the primary key of a table (through indexes, UNIQUE constraints, PRIMARY KEY constraints, or IDENTITY properties).2.Domain IntegrityDomain integrity validates the entries for a given column. Domain integrity can be enforced by restricting the type (through data types), the format (through CHECK constraints and rules), or the range of possible values (through FOREIGN KEY and CHECK constraints, DEFAULT definitions, NOT NULL definitions, and rules).3.Referential IntegrityReferential integrity maintains the defined relationship between tables when records are entered or deleted from the tables. In SQL Server 2000, referential integrity is based on relationships between foreign keys and primary keys or between foreign keys and unique keys (through FOREIGN KEY and CHECK constraints). Referential integrity ensures that key values are consistent across the related tables.When referential integrity is enforced, SQL Server prevents users from adding records to a related table if there is no associated record in the primary table. Users are also prevented from changing values in a primary table or deleting records from the primary table if there are related records in the related table.4.User-Defined IntegrityUser-defined integrity is used to define specific business rules that do not fall into any of the other integrity categories. All of the integrity categories support user-defined integrity. All column-level and table-level constraints defined in CREATE TABLE, stored procedures, and triggers are examples of user-defined integrity. About the Author:uCertify was formed in 1996 with an aim to offer high quality educational training software and services in the field of information technology to its customers. uCertify provides exam preparation solutions for the certification exams of Microsoft, CIW, CompTIA, Oracle, Sun and other leading IT vendors. To know more about uCertify, please visit http://www.ucertify.com/

Category : General Computer: Databases

Photography School

Author : Ross Bainbridge
If you have the desire to capture special moments and freeze them in timeless photographs, then you already have one key ingredient to becoming a good photographer. But, if course, you have to supplement your desire with training. Hobbyists can learn how to shoot with the most advanced cameras and deliver captivating pictures effortlessly. To be able to move on from being good to being great, it is encouraged that you seek expert training in a photography school.Photography schools are scattered all over the place and you should not have a hard time looking for one. There is no age qualification for most photography schools. What you would want to do is look at the portfolios of the instructors to see the level of their expertise and their reputation. Most distinguished universities offer photography courses and some even specialize in it. Here, more advanced students can go deeper in their photography training and get to brush elbows with the industry's elite.You would be taught how to use different cameras. You would learn the differences between a regular point-and-click camera from an SLR and the different lenses you can use to capture different images. Creative techniques, color theories, composition and the control of your photograph and pre-visualization could be part of your curriculum.To become a great photographer, you would have to learn how to play around with colors by using different films like black and white, color negative or color transparency both for digital and analog cameras and zone system. You also need to familiarize yourself with the equipment you would be using, the different type of flashes, the lenses, exposures and shutter speeds of your camera and how to get the proper light ratios.Photography School provides detailed information on Photography School, Online Photography Schools, Top Photography Schools, Digital Photography Schools and more. Photography School is affiliated with Interior Design Schools.
Category : Reference-and-Education:Vocational-Trade-Schools

More Than Meets the Eye to NASCAR Success

Author : Shay Rosen

The popularity of NASCAR has skyrocketed, making it one of the most watched televised sports in the U.S. today. For fans and spectators, the thrill of watching drivers maneuver the track at speeds that often exceed 200 miles per hour offers excitement beyond compare. For those in the industry itself, the behind the scenes action is also fraught with victory and defeat, which makes for a thrilling ride.Few who enjoy the sport from the outside realize just how much preparation, innovation and time is spent preparing engines, transmissions and the car bodies themselves for the long racing season. Technicians work tirelessly to adjust, refine and perfect every aspect of a cars performance while maintaining strict adherence to NASCAR regulations. Pit crews train together in order to maximize their speed and accuracy while minimizing the risk for serious injury to both themselves and the driver they will assist. All in all, their combined efforts are more likely to determine who will finish the season with the most points than anyone behind the wheel.These are no ordinary mechanics by any standard. Most diagnostics and pit crew personnel receive specialty training at facilities designed for those interested in working within the sport. These facilities, such as the NASCAR Technical Institute run by the Universal Technical Institute in a joint partnership with NASCAR, cater to both the industry itself and those who wish to be a part of it. Additionally, most graduates undergo extensive training developed by the respective racing teams they become a part of.For pit crew personnel in particular, the physically demanding aspects of the position require a great deal of stamina. Every active racing team on the circuit today incorporates physical conditioning as part of their training in order to increase stamina. Long periods of inactivity are intermittently infused with moments where the crew must work as a cohesive unit, and with not a moment to spare. Additionally, they must be at the ready through every lap, from the first to the last.For those who develop and diagnose performance standards for the cars, minute adjustments and constant testing are commonplace. From the timing belt and air intake to the aerodynamics measured in wind tunnel testing, their mission is to give their car, and consequently their driver, every possible advantage. The efforts they make can mean the difference between a pole position or starting the race at a disadvantage. So while fans of NASCAR are familiar with the victory lap and hoisting of the trophy, there is a quiet celebration among the unknown faces that comprise the racing team which spectators will likely never see. Without question, a win for the driver is also a win for the combined efforts of those who helped make a trip through victory lane possible. For more on NASCAR pit crew training from the NASCAR Technical Institute, visit our site. For online and campus based educational resources, visit 866MyMajor.com. For more on the NASCAR pit crew experience, visit our blog.

Category : General Automotive: Racing

Car Insurance Rates - 4 Tips for Preventing Car Theft

Author : Dean Larson

Having your car stolen can be a scary thing. Many who have had their cars taken typically feel both angry and vulnerable, even to the point of feeling somewhat "violated". If you don't have insurance that covers the theft of a car when it happens, it can be equally as scary from a financial point of view. When you have comprehensive coverage on your car, your insurance company will help to replace your stolen car. While having this coverage is important, there are some ways that you can help prevent your car from being stolen as well, which may save you money on your car insurance rates in the long run. As they say, an ounce of prevention is always worth a pound of cure.Tip 1: Use Common Sense - One of the best ways that you can prevent your car from being stolen is to use common sense and make sure that you lock your car doors whenever you leave your vehicle, regardless if it's in a dark alley, a public place, or parked in your garage. Plain and simple, if you leave your doors unlocked all the time, you elevate the risk of your car being stolen. You should also be sure that you take your keys with you and never leave them in your car or anywhere else in public. Often just using these common sense precautions is enough to save you from car theft.Tip 2: Get an Alarm - You can also help prevent car theft by installing some kind of warning device or alarm device in your car. Whether it is a visible device or an audible one, both can be good deterrents to anyone thinking about stealing your car. Usually alarms are fairly affordable, and it is definitely cheaper than trying to find a new car.Tip 3: Use an Immobilizing Device - Another way to prevent your car from being stolen is to purchase some kind of immobilizing device to use in your car. There are a variety of different devices available, such as smart keys, kill switches, the Club, and fuel cut-offs. Many of these devices are relatively inexpensive and they are highly effective as well. Tip 4: Install a Tracking Device - One of the newer ways to deter car thieves is to have a tracking device installed in your car. These devices are quite high tech, and they will alert you when someone is moving your car without authorization. Some of these tracking devices actually will notify the police when unauthorized movement is made as well. While these tend to be a bit more expensive than other methods, they can definitely be a great help if your car actually gets stolen.Even though you may have coverage on your car that will pay if it is stolen, taking preventive measures is much simpler and will help keep your car insurance rates down as well. Just taking the time to use common sense and employ the help of cheap devices can help keep your car from being stolen. While incorporating one of these tips is great, using all of them together can give you the best results when trying to protect your car from theft. To learn more about how you can save money and greatly reduce your car insurance rates, please visit car-insurance-rates-info.com. We offer unbiased information on the best ways to get insurance discounts, find out what average car insurance rates are, do company comparisons, and keep you safe and saving money all year long.

Category : General Business: Insurance

How to Analyze a Competitor's Website

Author : Halstatt Pires

Competitors' websites, if analyzed properly, can give you all
sorts of information that you can use to increase the traffic
and the popularity of your site. Here is an article on how to
analyze a competitor's website.

Identifying the Leaders

Start off by identifying the major players. A good place to do
this is Yahoo's directory. It is good to view the major players
in similar fields to your own so that you have a better view of
your web site as perceived by others. You may want to print out
the directory to take a closer look. Check some of the bigger
companies and find out some of the innovative approaches and new
products offered.

Sites like Media Metrix 500 can tell you which companies get the
most traffic, and you can learn about the relative traffic by
using Alexa. It is a free add-on to your browser that ranks the
traffic for each site you visit and informing you whether it is
in the top 100 or top 1000 ranking. This gives you a rough idea
of where your competitors are in the ranking order.

Scrutinize the Leaders

The next step is to study the top 5 or 10 competitors very
closely. There is a lot that can be learned by looking at
competitors' web sites and analyzing them. These are the things
that you should look for:

1. Make sure you check to see what products or services
competitors offer, and note anything that's different from your
own offerings.

2. Look for gaps that you could fill.

3. Think about the look, feel and functionality of the
competitors' web sites.

4. Check the advertising campaigns and offers they are running.

5. Look at their strengths and weaknesses, from the customer's
point of view.

6. See if you can figure out their strategy.

If you are dealing with a public company then you can get
detailed information from proper sources and write down the
names of their key players. Then it is possible to look for any
interviews, articles or speeches they might have made about
relating to their web site.

Look for Strengths, Vulnerabilities, and Gaps

Now summarize the information you have found into few sentences
for each competitor, highlighting the strengths and weaknesses
of each one. Note down the strategies to be followed to counter
your competitor's offering.

With this research, you can create or modify your marketing
plan. Be sure to include how you intend to deal with
competition, and what steps you think you would require getting
top rankings in the search engines. On the basis of your
research on your competitors' websites, you need to make a
decision of either to compete with your competitor or walk out
of the competition and focus on other areas.

Don't get frightened away prematurely, though - make sure you
know what you are getting into before you start, and don't let
big companies intimidate you. Remember that you can move faster
than your competitors if you have confidence in your abilities.
All you need to do is offer your customers things that they
cannot find anywhere else.

Category : Commentary

What Is Your Message?

Author : Micheal Savoie
Our technologically advanced society has forced us to go into isolation to get a break from the onslaught of information bombarding us from all sides. Radio, television, email, printed media (such as newspapers, books and magazines) and the Internet are all methods that people are using to get their message to each of us. Even in your car you get signs, billboards, bumper stickers and car decals shouting at you about someone`s message. If you were to undergo hypnosis and be made to read back everything you have read during the course of one day, you would be amazed at how many things were recorded by your brain.The fact that our minds are steel traps for information is not a new concept. Scientists for years have told us that our minds are amazing, that we can store unlimited amounts of information and that if we could harness the full potential of our brains, we would not need computers. Unfortunately, the retrieval process is the key factor in our inability to spout off what we know at critical moments (like during that Chemistry Test, or on our wedding anniversary). As people age, this process is even more challenged to the point that we forget more than we know.What does this have to do with your message? What is it that you want people to do when you write sales copy? If you answered "buy my product" you are correct, but the more correct answer is "take action." While every message is a sales message, what you are selling is not always a product or service that requires a customer to exchange money for it. Sometimes the message is designed to get someone to click on a link, fill out a form, write your congressman, or stop smoking cigarettes. The end result of the message can be someone "buying in" to your way of thinking.What about if I am not writing sales copy? An article is sales copy, even if there is not a product at the end of the story. You still are creating a situation where the buyer (reader) is either going to agree with your view (thesis) or disagree (you did not make the sale). When you successfully craft your message, the reader will agree with your line of reasoning and you have made the sale! Congratulations.I write to let my mind release the pent up intelligence that it often does not have a chance to let out in my day to day encounters. Not everyone agrees with my way of thinking and I accept that. In fact, my goal is to reach people who may not think the way I do and to potentially allow them to see a different perspective. I would be elated if that resulted in turning someone from "the Dark Side" when they initially did not agree with me, but I am fine with the idea that I may not have influenced anyone with my musings. My hope is only to touch people with kindness or at least positiveness, and to give a little of that experience that my fortysomething years on this planet have taught me.I know, that last statement makes me sound like an alien. Technically I am not an alien, because I was naturalized back in the 1980's, so now I am non-alien. Almost human. My wife would happily tell you that I am very much human, too human. But I love her anyway.When you write, how are you putting your thoughts across to your audience? Do you go for shock value? Do you entertain? How much of your personality comes out in your writing? Again, I will repeat that you will not relate well to everyone who reads your writing. Just make your message as palatable to as many readers as possible without watering down your content. You want to inform and at the same time touch each reader with your personality and give them a chance to get to know you. If you follow this strategy, you will develop a group of people who will eagerly await your next article or book. Some will eagerly await your emails if you are just sending out newsletters.Plan out your message before you get too involved in the writing. Outline as much of your message as you can before you begin fleshing out the details. Think of an outline as the skeleton of your message, and the words you use to blend each section together are the muscles, organs and tissue of your story, e-book or novel. I remember reading Piers Anthony`s comments at the end of one of his books and how he said he never wrote a book until he had sold the story to the publisher. He said he would completely outline the story and send that to the publisher, and after he got the nod from his publisher, he would fill in the details of the story, following his outline as the guide for the adventure that he created for his readers. His success using this formula is proof that you should be planning your writing so that you can keep yourself as organized as possible.Imagine the time savings of putting your outline in front of you and then writing your article based on your outline. You will not be deviating from the course you set out, because every time you pause to see where you are, you get a reminder of the next topic, and you can flow into the next section from one paragraph into the next.While I did not want to get into the mechanics of writing (I have to follow my outline), the flow mechanism mentioned above is a great method for keeping a reader intent on your message. If you can hold a reader's attention for long periods of time, you can cash in by having them devour your other works in the future. Who doesn't want a loyal following of prose-starved readers?Are you ready to reach out to the world with your message? The Internet is a canvas, and your words are the paint, and you are the artist who can take the plain, vacant canvas and turn it into a work of art that people will want to tell their friends about. And after all, isn't that the end result we are trying to get for our message anyway? Your words, being passed from person to person virally, infecting more and more of your intended audience as though it had a mind of its own.It has a nice ring to it, doesn't it? Your message. Especially if you hear someone else passing it on to their friends. So what is your message? I'd really love to hear it.Micheal Savoie can be found at his blog: michealsavoie.com/welcome when he is not setting up his Viral Attitudes Seminar Series. If you want to be updated on the next location and date of Viral Attitudes Seminars, sign up for his informal newsletter at viralattitudes.info/notify so you can be the first to know. If you are speaker and would like to join the Viral Attitudes Tour, post a note to Micheal on his blog, and he will get back to you straight away!
Category : Self-Improvement:Creativity

Jumeirah selected to manage new seafront development in Palm Jumeirah

Author : PR Sending

>April 19th, 2007