SQL table constraint limit number of same domain < 5
constraint in oracle
How to parse hex values into a uint? uint color;  bool parsedhex = uint.TryParse(TextBox1.Text, out color);  //where Text is of the form 0xFF0000 if(parsedhex)    //...   doesn't work. What am i doing wrong? Will Winterbash promote mass spamming due to its short time frame? Is there any concern that , due to their time-limited nature, will encourage mass spamming of posts? Cosmopolitan, for example, can only be achieved by posting to Meta. There are over one million users on Stack Overflow who may want this hat, and have only until January 4th to get it, and their only means of doing so is to invent some reason to post to Meta. My boss gave me a task with completion date suppose 31 March, 2017and I completed on 28 February, 2017. Is it in time or before time. Ralink MT7601U (148f:7601) Wi-Fi adapter installation I would like to enable the root account on my Ubuntu installation.  I realize the security implications of this. I'm downloading some images from a service that doesn't always include a content-type and doesn't provide an extension for the file I'm downloading (ugh, don't ask).  What's the best way to determine the image format in .NET?  The application that is reading these downloaded images needs to have a proper file extension or all hell breaks loose. Is Linux Virtual Server old, or is it standing still? Based on this question: , LVS may be the right solution for my problem.   But when I went to its homepage , I found that LVS has been updated since Nov, 2008. The world's moving fast, and I don't know if LVS was obsolete or not.  Is LVS standing still, or there're some better solutions to replace it?  Thank you so much. Proof for $e^z = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{z}{x} \right)^x$ Q1: Could someone provide a proof for this equation (please focus on this question):   $$e^z = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{z}{x} \right)^x$$  Q2: Is there any corelationn between above equation and the equation below (this would benefit me a lot because i at least know how to proove this one):  $$e = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{1}{x} \right)^x$$ Marketing Cloud Mobile Push SDK - Switching app user I'm currently building a clienteling app that integrated the Mobile Push SDK on both iOS and Android and encountered some issue on switching the account.  I found that when I login to user A, and set contact key to A, the Inbox Messages will be send to this device. However, I logout user A and switch to a user B, I should set the contact key to B. But seems the inbox messages are associated with the Device instead of Contact, I can still see the inbox messages that were sent to contact A previously.  My question is, how should we deal with this situation, to prevent from seeing the previous inbox messages if the contact key has been changed? Why do I have blurred vision and how do I fix it? Render semi-transparent volume with cycles Whole disk unallocated? Gparted error or partition overlapping? How can I block all ports except some? I am trying to use iptables but I am clueless in understanding the documentation even so that I've locked myself out of my server twice already whilst trying to implement it.  These are the simple rules that I want to implement:   Allow ports 80, 6667 and 6697 to everyone Allow port 22 to just my IP for example 10.10.10.10   Please can someone help me implement these simple rules, without locking myself out? Square roots not on same height This part C\frac{1}{\sqrt{G}}\sqrt{\rho} doesn't seem to be on the same height as this part \sqrt{b}\sqrt{l} when compiled. What am I doing wrong?  \begin{flalign*} T=C\frac{1}{\sqrt{G}}\sqrt{\rho}\sqrt{b}\sqrt{l} &amp;&amp; \end{flalign*} Mail on Big Sur does not reliably find dollar values If you hash a string using SHA-256 on your computer, and I hash the same string using SHA-256 on my computer, will we generate the same value? Does the algorithm depend on a seed (so we'd both need the same seed) or some other such parameter?  edit:  To clarify, by 'string' I meant 'the same byte input', which as the comments and @ispiro's answer point out, may be different for the same character string depending on the encoding. How to create a scope? I'd like to create a custom scope that searches and returns results from an online source for personal use.  Is this possible? And if so, how? Can open sets and closed sets of $\mathbb{R}^n$ be homeomorphic? Suppose $A$ is an open subset of $\mathbb{R}^n$ considered as a topological subspace. Suppose $B$ is a another susbet of $\mathbb{R}^n$, and under the induced topology, is homeomorphic to $A$.  If $B$ is closed and bounded, then by the Heine-Borel theorem, $B$ is compact as a topological space so $A$ and $B$ cannot be homeomorhpic, because $A$ is not compact. But if $B$ is not bounded, what can be said about $B$, if any? Must $B$ be open, can it ever be closed (let's leave out the only case of being both open and closed--the entire ambient space $\mathbb{R}^n$), or can it be neither open nor closed? It is a general concept that horizontal forces can only influence physical quantities along horizontal direction; similarly vertical force can produce acceleration etc. only along vertical direction. This is the same concept that helps us study projectile motion as a combination of two independent motions. If this relation is universally true, how come, then friction depend on a force which normal to it? Minecraft extra folders? Once I click to run minecraft a small window appears saying "Downloading runtime", then three other folders appear onto my desktop: Game, Native Log, and Runtime. This really annoys me, as I have to keep deleting them after I am done with a session of minecraft. Why is this? It never use to happen before.