I would like to know about the advantages and disadvantages of primary key, foreign key and unique key. Is it possible to use two null values in unique key?
 

Hi,

I’m just new on this networking set-up. I hope i could get some idea here. I’m planning to set up small network at home. I have two PC, that i want to network. I want them in a 1 workgroup. I configure it in properties -> sharing. How come I could access them in the other computer? Even disabling firewall on 2 computers. I don’t have any idea what happening here.

Solution please.

Hello everyone. I want to replace my Dell Inspiron E1505's Random Access Memory from 512 Duo to 2-1GB memory. There are 633 Megahertz in the 512 one. What I want to know is, is it safe for me to install two 1GB 667 MHZ? Or do I keep the 533 Megahertz? Thanks in advance. 

What are the measures that I need to take in recovering from the crashing of a server, without losing the consistency of the AFS with stateful distributed file system? Please help.

Does anyone know how I can switch on my screen? That person seems to be a real noob, or not in his right mind. Either that or he does not have basic computer skills. He does not seem to know what a screen is. In an attempt to solve his issues, we told him that his screen was already switched on. In reply to his, he asked us where! 

Hello, I have an issue here. When my PC is switched on, I get an error message saying that spyware has been found on my PC. It also says that I should install an antivirus or antispyware in order to fix this. What do you suggest I do??

If a tag was built with an apparent meaning but afterwards started meaning something else, what should be done?? For instance, .cdr tag was built as a CorelDraw file ext, but afterwards it was utilized as a CD-R-Disc by 2 users . Correct me if I am wrong, but I imagine that the solution is to create a cd-r tag, then retag 2 queries, and afterwards add tag descriptions for both.  What I am not confident about is, if a tag started meaning something else, does it replace the 1st one? 

Do you know how I can get answers to an archived question like this one? I hope that software questions like this have been updated in the past, to enable new users to learn from your experience. By the way, where do I post to request that a question be updated??

During the process of turning off my PC, all the icons on my desktop disappear for some time, and then reappear. Does this happen, or is somebody accessing my PC through a backdoor or something? I have AVG antivirus on this PC, but I am still anxious.  This is why I am seeking advice from you professionals out there. Please help!

How to define modeling and what are the advantages of developing a model? Moreover, I want  know exactly, where the Admin model is included in an ATM machine processing system and the number of possible models that can result in its successful functioning. ..