Should be a fairly simple question, 5 stars to the most elaborate answer. Figure
ID: 3533898 • Letter: S
Question
Should be a fairly simple question, 5 stars to the most elaborate answer.
Figure 2 is an E-R diagram that is an attempt at a design for a database that will include information about Web servers and the URLs of pages at those servers. For each web server we want to represent its IP address, (e.g.165.323.5.23), its registered name (e.g. domain com ) and the name of its webmaster. We assume a webmaster can be in charge of only one server. Give the two most important things that are wrong with this design. Explain how you would fix the problems and give an improved E-R diagram.Explanation / Answer
There is nothing wrong in your design. But, being an IT guy, i can see several difference in views. This design can be improved. Image will be cropped here. So, I am uploading it on two image hosting sites. In case one gets deleted, other will work as back up for you. http://i38.tinypic.com/2z53g28.jpg http://s8.postimg.org/cv7jfdmid/img.jpg 1. Nobody knows your Webmaster by name. That can never be a primary key. Say, if your name is Alex. There can be many more Alex in the company. So the employee id is the better idea for the primary key. If your webmaster is some kind of readymade tool. Again rather than name, its identification number can always be a better basis to track things. Later it will always be easy to track things. Hence, as per me, there should be two fields in webmaster. a. ID b. name Infact, its always a good practice to associate your each entity with a primary key for a stronger database design. 2. Mapping has been left out. webmaster to web server will be 1 :1 mapping. (as your requirement specifies.) web server to URLs will be 1: N mapping (as one server will keep track of several URLs or pages.) 3. I strongly believe, that here in URLs too, u need to add IP address because every live site has its own IP address. Names are just for us to remember. Every Site have an IP address. just because we cant remember so many digits. we run it using names like google.com. From my location, google.com works fine by just entering http://74.125.236.166/ in my browser. In case your webpages are offline, u can remove this field. else you can give them some private IPs.
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