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Web Hosting - Databases, What Are They and Do You Need One?
'Database' is one of the most commonly used terms that one encounters in web site design. Yet, what they really are and whether they're essential is often not clear to novices.
A database is a collection of organized data, stored in files that have a specific structure. It's that organization and structure that allows for easy and rapid storage and retrieval.
The need for a database generally only arises when you have a certain amount of information and that information needs to have some structure. If you have a half-dozen names and addresses to store, a database is usually overkill. If you have a blob of data with no relationships between any of the items in that blob, maintaining a database is usually more trouble than it's worth.
Maintain a database? Yes, like other complex systems a database, to be effective, needs to be designed properly at the outset then kept 'tuned' for good performance. The alternative is to gradually allow the database to become more and more disorganized. That leads to difficulty in use, poor speed of retrieval and more frequent failures.
With MySQL, Access or MS SQL Server, the three most common choices of database product for web sites today, setting up a database is relatively simple. Even those with limited technical skill can get one up and running just by following some simple instructions. But some thought should be given to how you want the information organized, and to maintaining the system during its lifetime.
Suppose you have a set of names, addresses, email addresses, products purchased, date purchased and amount. If you have only a few dozen records it matters very little how these pieces are arranged and related. A database usually isn't even warranted in this scenario. Once you have several thousand or more records, it matters a lot. Speed, the ease of expanding the set of attributes (like adding, say, product category), and other issues come into play.
Even those with little technical expertise, but a willingness to exert logical thought and invest some time, can build a very robust database. Think about how you would organize a set of data (called 'tables'). Should Name, Address, and Product be in the same table? Or should the personal information be stored in one table and any product information (product, price, ...) in another?
Some experimentation may be needed to get it right, but the choices have an impact on how easy the tables are to maintain. It also affects the speed with which programs can fetch old data and store the new.
Having a database also introduces new maintenance issues for the server administrator, since backups usually need to be done differently. Recovering a failed database is usually more complicated than simply re-copying files from yesterday. Ask your hosting company what tools and skills they have for dealing with any database system you consider.
It's true that introducing a database creates more complexity and the need for additional thought and administrative effort. At a certain level, professional expertise will be needed. But clearly the advantages outweigh the costs in many cases. Companies large and small eventually use databases to store and organize data. At some point, you may be fortunate enough to be one of them.
Web Hosting - Domain Name Changes and How They Affect You New domain names are registered all the time, and ones previously registered expired. Sometimes that's the result of simple neglect. The owner of the name chose not to renew his or her ownership, so the name became available for someone else to use. In rare cases, a highly original mind managed to think of a new one. In the other common scenarios, someone chose to just let it go or sell it. When you choose to change your domain name, there are actually two separate steps involved: releasing the old name, and adopting the new one. But, just as the postal system can have difficulty forwarding your letters when you change your personal name, changing your domain name brings certain difficulties. One of the most prominent is the fact that any name change requires a change to thousands of DNS Servers around the globe. DNS (Domain Name System) is the set of software/hardware components that allows domain names to map to IP addresses. IP addresses are what are actually used 'under the covers' when one computer communicates with another. Note that there isn't always a 1:1 correspondence between a name and an IP address. One IP address can serve multiple domain names and one domain name can have multiple IP addresses. For the sake of simplicity, we'll stick to the common case here. DNS servers around the world maintain internal databases that match the name to an IP address. Not all servers have all pairs of names/addresses. A series of complex routines allows a request to be forwarded when the particular DNS server doesn't have a needed record. When you acquire a domain name that used to be associated with a given IP address, the odds of you acquiring the same IP address are extremely low. In the unlikely case, for example, that you acquired the domain name yahoo.com, you would almost certainly not get the IP address that was matched with it (unless you bought the Yahoo! company). So, as a result of the change, the name/IP address pair is no longer what it was. A similar circumstance exists when you retain your IP address, but want to change the domain name associated with it. In either case, the pairing has changed. The catch is this: when the change takes place, those DNS databases are not all updated instantaneously around the world. Even apart from the limited speed with which computers and networks operate, (and neglecting the human factor if/when the change is made manually to more than one server) the reason is something called caching. In order to communicate efficiently, DNS servers are designed to assume that changes will be relatively rare. Just as with the postal system, you don't move your address or change your name every minute. Since that's true, in general, the name/IP address pair is cached. A cache is a set of stored information that is reused so that fresh information doesn't have to be communicated with every request for a web page or data. A chain of DNS servers pass requests to the last known address. There is usually more than one system between your computer and the server you want to communicate with. Most of the time, that's your current name/address. When you change the name, that pair is no longer valid. In order to propagate the new name/address pair (so the terminology goes), that cache has to be refreshed. Something similar happens when you establish an entirely new name. That name is first associated with an IP address and that pair has to be communicated to DNS servers around the world in order for you to be able to reach any one of them at random. But DNS servers don't do that until they are requested to do so by your action of asking for information from a remote server. Because of that, but chiefly because of caching, it can take quite a while for the new pair to become known around the Internet. Caches can expire and get refreshed in a few minutes or a few hours. It varies. That time can be as short as an hour or less, if the path between your computer and the web server is very simple and only one DNS server needs to be updated. Or, it can take up to 48 hours or more. Though the 'official' range is often given by registrars as 24-48 hours, the average is closer to about six hours. But that's an average. The actual time in any given case can (and does) vary widely. In the meantime, a number of effects can occur. The most obvious is that, since the name/IP address pair can't be resolved properly, you don't reach the server you want. Your browser points to the old one (in the rare case it's still accessible by that name and address), or it simply reports there's no such name at that address. So, when registering a new name or buying an old one, you should establish the site, but not advertise it for at least a couple of days. Better to wait to get visitors than to turn them off by being 'not at home' when they call.
Do and Don’ts of the Interview Process No one likes job interviews. From the moment you schedule the interview you are under a microscope. Your potential employers waiting for you to make the move that make you stand out or eliminates you from being a candidate for the job. This necessary dance that just about everyone, has to go through can be mastered. Learn the key things to do to become a high-ranking candidate for a job. First of all, before you go to the interview be prepared. Having copies of your resume and pens are only half the battle. Where exactly is the office located? Do not leave the location or the interview site up to chance. The only way to know exactly where your interview is and how much travel time you should allow is to go there. Even if you are interviewing out of town, find out how long the drive is to the interview. Nothing disqualifies you, in most cases, faster than being late for your interview. Before you are sitting across from the interviewer, accumulate some knowledge about the company. Knowing about the position is not enough. Everyone that interviews will have read the advertisement for the position. You need to be armed with information about the company. Have they won any service awards? Are they ranked as one of the best companies in America to work for? Find out and impress the interviewer. Another way to impress the interviewer is to have intelligent, thoughtful questions to ask. Ask about productivity, benefits or training procedures. Show that you have done your homework and are truly extend about the position. Be attentive and bring the interviewer as much information as possible about yourself. If you have a portfolio or reference letters, be sure you take them to the interview. Also be prepared with complete work history and information as well as past residency information. Be ready to answer a few probing questions. Why do you want the job you have applied for? What makes this a good time for a job or career change? Have some intelligent answers for these questions. Interviews will know if you are nervous. No matter how badly you need the job, do not appear desperate. Show that you believe in yourself and are confident about your ability to do the job. Speak in terms of when you get the job opposed to it. While this is a bold move it is a way to reinforce the idea of you being chosen for the job. This is a trick for both you and the interviewer. No matter how true this may be, never tell the interviewer that you “really need a job”. If this is what you tell the interviewer they will think that you are willing to take any job. Also, never talk negatively about your current boss or co-workers. Give as objective view as possible if you are asked about your current job relationship. Inquire about the next interviewing steps. This will not only show the interviewer that you are interested in the position it will also give you some time to prepare if you are called for the next interviewing step. Be sure to keep a notebook in your car so you can jot down notes immediately after you leave the interview. This is the best way to keep track of important facts about the position. In a day or so, mail a thank you card to your interviewer. This could be the added interest they are waiting to see from you in order to eliminate the other candidates.