How to create a foreign key to multiple tables?
Possible to do a MySQL foreign key to one of two possible tables?
Avoiding GeoServer/Java out of heap space error? I'm new to Geoserver, Ubuntu and Java, but have downloaded a virtual machine from gisvm.com and am getting up to speed. I got as far as configuring it with some fairly large shapefiles from a project I've worked on previously.  My question is related to a problem which I see if I show the shapefile using the OpenLayers layer preview option. I see an error:     OpenLayers map preview code="internalError" Rendering process failed.   java.lang.OutOfMemoryError: Java heap space   Googling has led me to plenty of Java command line options to increase heap space, but I have no idea if this should be applied to an environment variable, in a startup script or as a part of the Geoserver config.   Can you help me to understand what I need to edit to get this working?   I'm also wondering if I should be splitting my shapefile into smaller pieces. An insurance company supposes that the number of accidents that each of its policyholders will have this year is Poisson distributed, with a mean depending on the policyholder: the Poisson mean Λ of a randomly chosen person has a Gamma distribution with the Γ(2, 1)-density function fΛ(λ) = λe−λ (λ > 0). Find the expected value of Λ for a policyholder having x accidents this year (x = 0, 1, 2, . . .).  I am not sure how to incorporate the gamma parameters. So far I have found P(X = n|Λ = λ) = Poisson(λ) and fΛ(λ)= Exp(λ) so by integrating P(X = n|Λ = λ)fΛ(λ) then letting the integral of Gamma (n + 2, 2) equate to 1, I have worked out P(X = n) = (n + 1)/2^(n+2). How do you find the expected value of Λ from that? I have seen that a Gamma-Poison mix has E(X) = αβ which would give 2 but I have tried integrating fΛ(λ) and can't seem to get 2. Whence came the different varieties of the "long i" diphthong? What is the origin of “long long i” before voiced consonants (the [ai] of wide, while, &amp; tribe) versus “short long i” before unvoiced consonants (the [ʌi] of white, wife, &amp; wipe)? When did this difference appear? Is it just a secondary distinction, or are there minimal pairs for these two diphthongs?  Obviously the distinction is not present in all accents—though its presence in most leads me to believe it's not a late arrival—and yet I've never found a dictionary that distinguishes them. After deleting all nodes, how do I reset the node ID to start from 1 again? I generated tons of dummy content for testing, and then deleted them all.  As nid is auto-increment, newly created node will have a nid of last created nid +1.  How can I make nid start from 1 again? For a prime $p \equiv 1$ or $3$  (mod $8$), show that the equation $x^{2} + 2y^{2} = p$ has a solution.   I'd like to see an elementary proof. Clean way of building simple taxonomy browser of arbitrary depth AWS S3, Paperclip missing required :bucket option Combining Multiple Lists Singular or plural verb with two subjects Possible Duplicate:          I'm writing an interrogative sentence questioning someone else's writing:  "Is grammar and spelling correct?"  Can I use the singular verb "is" or must it be the plural verb "are"?  (The sentence is one of a list of interrogative questions about the quality of writing, e.g. "Are words in the right order?" "Does the copy flow?") About big parenthesis larger than Bigg How to prove $\sum_{n=0}^{\infty} \frac{n^2}{2^n} = 6$? I'd like to find out why  \begin{align} \sum_{n=0}^{\infty} \frac{n^2}{2^n} = 6 \end{align}  I tried to rewrite it into a geometric series  \begin{align} \sum_{n=0}^{\infty} \frac{n^2}{2^n} = \sum_{n=0}^{\infty} \Big(\frac{1}{2}\Big)^nn^2 \end{align}  But I don't know what to do with the $n^2$. I was having trouble playing the game on my android so I downloaded it to my wife's phone (Galaxy S6). I read some posts on how to get it running on my android and it worked but, my level 7 account is on my wife's phone.  How do I get it back to my android? When I sign out and back in it doesn't ask for any sign in info. I've tried deleting the app's data and even uninstalling and re-installing, but it still doesn't ask for sign-in info. Can an electron be in two places at the same time? So I've been reading a bit and watching some videos about the double slit experiment, and therefore the wave particle duality; I've also read this "implies" that a particle can be in two places at the same time. Can you clarify this, and how could that be possible? I'm on Ubuntu 16.04.1 at the moment, and system windows like the Files window, Terminal or System Software open behind the Unity launcher, which means they are partially hidden behind it. I can move them with Alt+F7, but I'd like a more permanent solution to this problem. Extract float/double value How do I extract a double value from a string using regex.  import re  pattr = re.compile(???)     x = pattr.match("4.5") Custom Gmail labels sort I want to sort the labels in my own order instead of the default abc order, so that, for example, the label named bills should come up first.  Any way to do that? Subgroups of finite abelian groups. For every subgroup $H$ of a finite abelian group $G,$ there exists a subgroup $N$ of $G$ such that $G/N \cong H.$ I need to prove this or give a counter example.  I am aware of isomorphism theorems and classification of abelian groups, direct products etc. How do I create a PPA? How do I create my own custom PPA to share with the Ubuntu community? I am trying to create my own custom package set and I would really like to share it with the community. What's the best and quickest way to detect whether you're running a 32 or 64-bit version of Windows Server from the command line?  (Cygwin is installed) Multiple TikZ keys with foreach