MS Access VBA: Are Object Variables necessary, when they aren't used, beyond the scope in which they are declared? I often see code examples, that go through the laborious and possibly confusing process, of declaring, setting, calling, and any associated cleanup, of Object Variables, that otherwise, work fine without the variable - least of all, on a variable that is Private to that function.  Is this at all really necessary, when writing out the full reference, does just as well?  I've heard arguments, that the code is easier to read, and runs faster. The former is highly subjective, and the latter, I have yet to really notice.  Examples;  Public Sub TransactionExample()      Dim wrkSpaceVar As DAO.Workspace     Dim dbVar As DAO.Database      Set wrkSpaceVar = DBEngine(0)     Set dbVar = CurrentDb      On Error GoTo trans_Err     wrkSpaceVar.BeginTrans      dbVar.Execute "SomeActionQuery", dbFailOnError     dbVar.Execute "SomeOtherActionQuery", dbFailOnError      wrkSpaceVar.CommitTrans      trans_Exit:     wrkSpaceVar.Close     Set dbVar = Nothing     Set wrkSpaceVar = Nothing  Exit Sub  trans_Err:     wrkSpaceVar.Rollback     MsgBox "Transaction failed. Error: " &amp; Err.Description     Resume trans_Exit End Sub   vs  Public Sub TransactionExample()      On Error GoTo trans_Err     DAO.DBEngine.BeginTrans      CurrentDb.Execute "SomeActionQuery", dbFailOnError     CurrentDb.Execute "SomeOtherActionQuery", dbFailOnError      DAO.DBEngine.CommitTrans  Exit Sub  trans_Err:     DAO.DBEngine.Rollback     MsgBox "Transaction failed. Error: " &amp; Err.Description End Sub   I am not asking about setting variables to "Nothing"; I am asking if they are necessary at all. And for what it's worth, necessary, within the scope, of the examples provided.
Is there a need to set Objects to Nothing I always read that it is recommended to set objects to nothing, once I am done with them. But I normally use them only in functions inside forms.  Isn't the reference lost and memory released when the function scope is left, regardless of setting objects to Nothing?   i.e. is it really necessary to do:  Set db = Nothing Set record_set = Nothing
I changed my hostname, why is my bash PS1 prompt unchanged? Isomorphism between $\Bbb R$ and $\Bbb R(X)$? My questions are:     $1.$ Is there a field morphism $\Bbb R(X) \hookrightarrow \Bbb R$ ?      $2.$ If the answer to $1.$ is "yes", are $\Bbb R$ and $\Bbb R(X)$ isomorphic as fields?   $ $    $ $  For $1.$, here are some comments:   This is true for $\Bbb C$, see . The key point here is the fact that $\Bbb C$ is algebraically closed, of cardinality $2^{\aleph_0}$, and of characteristic $0$. The same argument doesn't work for $\Bbb R$. We can actually find a subfield $F$ of $\Bbb R$ such that $F \cong F(X) \cong F(X,Y) \cong \cdots$, see .  that $\Bbb Q(X)$ does not embed in $\Bbb Q$ (as a field).  This is equivalent to: Is there an injective ring morphism $\Bbb R[X] \hookrightarrow \Bbb R$ ? (By taking the fraction fields).   As for 2. :   They are isomorphic as abelian groups, and actually as $\Bbb Q$-vector spaces. They are not isomorphic as $\Bbb R$-algebras, because they haven't the same transcendence degree over $\Bbb R$. Let's try to see how to construct such a field isomorphism. We could try$^{[1]}$ to find a subset $B$ of $\Bbb R$ such that $\Bbb R = \Bbb Q(B)$ and $C \subsetneq B \implies \Bbb R \neq \Bbb Q(C)$.  The set $B$ must contain transcendental elements, pick such an $x_0 \in B$.  Then $\Bbb R = \Bbb Q(B) = \Bbb Q(B \setminus \{x_0\})(x_0)$ and we could try$^{[2]}$ to find a field isomorphism $\Bbb Q(B \setminus \{x_0\}) \cong \Bbb Q(B)$, so that $\Bbb Q(B \setminus \{x_0\})(x_0) \cong \Bbb Q(B)(x_0) \cong \Bbb R(X)$.  For ${[1]}$, I tried to use Zorn's lemma on $\mathscr B = \{B \subset \Bbb R \mid \Bbb R = \Bbb Q(B)\}$ and the partial order $B_1 ≤ B_2 \iff B_1 \supset B_2$. But this is not clear to me why this should be an inductive set.  For ${[2]}$, my idea was to define $f : \Bbb Q(B \setminus \{x_0\}) \cong \Bbb Q(B)$ by choosing a bijection $b : B \setminus \{x_0\} \to B$ (these sets should be uncountable), and then trying to extend $f\vert_{B \setminus \{x_0\}} = b$ to a field morphism.     Edit for $^{[1]}$: in  article (MINIMAL GENERATING SETS OF GROUPS, RINGS, AND FIELDS, by LORENZ HALBEISEN, MARTIN HAMILTON, AND PAVEL RUZICKA) the theorem 2.4. proves that $\Bbb R$ has no minimal generating set as field (or $\Bbb Q$-algebra, i.e. as ring). The argument uses Artin-Schreier theorem. Minimal generating sets of modules are   .  I think that $B$ is a minimal generating set of a subfield $K \subset \Bbb R$ over $\Bbb Q$ if and only if any element of $B$ cannot be written as a rational fraction of other elements of $B$. Under these conditions and using (transfinite) induction, we can probably prove (and this was my first idea) that any function $f: B \to \Bbb C$ such that $b$ and $f(b)$ are conjugate over $\Bbb Q$ (i.e. have the same minimal polynomial) extends to a (unique) field morphism $\sigma : K = \Bbb Q(B) \to \Bbb C$.  Actually, the collection $\mathscr B$ defined above doesn't have to be an inductive set, at least if we replace $\Bbb R$ by $K =\Bbb Q(\sqrt 2, \sqrt[4]{2},\sqrt[8]{2},\dots)$, because the descending chain $\left(E_n = \{\sqrt[2^m]{2} \mid m \geq n\}\right)_{n \geq 1}$ satisfy $K = \Bbb Q(E_n)$, but $K \neq \Bbb Q\left(\bigcap_{n≥1} E_n\right)=\Bbb Q$, so the chain has no upper bound w.r.t. $≤$ in $\mathscr B$. Better than premium If $|z_1|=1,|z_2|=1$, how can one prove $|1+z_1|+|1+z_2|+|1+z_1z_2|\ge2$ Usage of singular or plural SI base units when written in both symbol as well as name I have multiple doubts related to the usage of singular or plural SI base units when written in both symbol as well as name.  I have framed this question under two parts, namely, Part (a) and Part (b). Each part has three sentences which I have written on the basis of my understanding.  Please answer these 6 sentences/questions.   Part (a):   says that while using prefix for e.g., centi as in centimeter, it is   l = 75 cm long.(correct) l = 75 cms long. (wrong)    Does this rule is used for all SI prefixes (having powers of 10)? In this regard, we should be saying, or writing that, "how many cm are there in one metre?" (while saying we should say centimter or centimetres?) Please strike-through the wrong SI unit in the following sentences.  My weight is 70 kg / kgs,  or My weight is 70 kilogram / kilograms.   Part (b):  and the page next to above web link says, we should write:  2.6 m/s, or 2.6 metres per second.   In this regard, we should say, or write:   Its speed is 0.26 metres per second.  This pipe is 0.75 metres long. How many cm are there in 2 metres? I'm having trouble understanding the simple "planetary" model of the atom that I'm being taught in my basic chemistry course.   In particular,    I can't see how a negatively charged electron can stay in "orbit" around a positively charged nucleus. Even if the electron actually orbits the nucleus, wouldn't that orbit eventually decay?  I can't reconcile the rapidly moving electrons required by the planetary model with the way atoms are described as forming bonds. If electrons are zooming around in orbits, how do they suddenly "stop" to form bonds.     I understand that certain aspects of quantum mechanics  to address these problems, and that there are  of atoms. My question here is whether the planetary model itself addresses these concerns in some way (that I'm missing) and whether I'm right to be uncomfortable with it. As soon as I start SQL Server with no application querying, in the task manager it starts to consume memory very fast till it consumes around 15GB. How can I resolve this issue? Why are my sauces splitting? If perimeter of a triangle is $2d$, what is the length of sides so the triangle has maximal area?    I found some solution using circle and angles, but I think I have to use derivatives.    I need help. What are the best JVM settings you have found for running Eclipse? I have 3 folders with large amount of data in each which has to be maintained seperately. Can I create a sym link or shortcut.in windows which should show me the merged contents of the 3 folders. I am not looking for library conf in Win7.   Any suggestion is highly appreciated. "Total number of votes for 'N' answers" is wrong in "Deleted Recent Answers" Below are the two screenshots. First one shows the number of votes          In above image a post which was deleted shown ) votes. Now in below image which is actual post deleted is having 1 vote. Finding an expression for $\tan (a+ b + y)$ which involves only $\tan a, \tan b,$ and $\tan y$. What does kill 0 do actually? In the man page, it says:  kill [ -s signal | -p ] [ -a ] [ -- ] pid ...  pid... Specify the list of processes that kill should signal.  Each pid can be one of five things:           0      All processes in the current process group are signaled   And I tried like this in bash:  $ man kill &amp; [1] 15247 $ [1]+  Stopped                 man kill $ kill 0 $ ps 15247 pts/41   00:00:00 man   Here 0 is used as pid. As I understood, kill 0 will kill all processes in the current process, which includes pid15247. However, it didn't do anything in this example. Does anyone have ideas about how to use it? Why did the slaver in Astapor think Daenerys wouldn't do exactly what she did? Spoilers! (do I have to even say that here?)  I recently rewatched the episode of Game of Thrones where Daenerys is in Astapor. She makes the deal with the master slaver guy, where she trades him one of her dragons for 8,000 of his very tough slaves. I immediately thought this was stupid for two reasons:   Why would he think the dragon would immediately obey him rather than her? Maybe he doesn't quite believe the 'Mother of Dragons' lore, but it's still basically a pet at the very least. This one isn't as bad though, as... Why would he possibly think she wouldn't betray him and use her freshly bought slaves to take back her dragon? He just traded her literally all his slaves and he has not been kind to her so far. He has motivation to not go back on the deal -- he's running a business, basically... but she has no reason not to.   I guess you could argue that he was blinded by greed, but I think that would be poor writing -- he's in a vicious trade, I can't imagine he would've survived long thinking so naively.  Does anyone have a good explanation? I just moved to a new computer: Windows 10 with XAMPP. As far as I know I set everything up the same as it was on my old Windows 7 computer. But now, for some reason, much of the time when I run drush cc all or run update.php, the database gets corrupted. Most frequently, some cache tables' *.idb files (tablespaces) are deleted from my mysql directory, which makes those tables appear as "in use" in phpMyAdmin and prevents them from being edited or emptied. They are always cache tables and never tables that actually get modified by my update hooks. Restoring the database is the only way to fix it then. This is a mature site that I've been working on for a long time, and have never seen this until the new computer. What's happening here?  A sample error message when using update.php, caused by a missing *.idb file:  PDOException: SQLSTATE[HY000]: General error: 1812 Tablespace is missing for table '(null)': DELETE FROM {cache_field} WHERE (cid = :db_condition_placeholder_0) ; Array ( [:db_condition_placeholder_0] =&gt; field:message_type:6 ) in cache_clear_all() (line 168 of C:\&lt;path&gt;\includes\cache.inc).   My most recent drush cc all error message, which Google has never even heard of, was:  exception 'PDOException' with message 'SQLSTATE[HY000]: General      [error] error: 1030 Got error -1 "Internal error &lt; 0 (Not system error)" from storage engine InnoDB' How to say the /p/ sound in the middle of words? I'm not sure how to say the /p/ sound in the middle of words like apple, puppy, happy etc. Those "p" sounds have a puff of air or not.  For myself I think those /p/ sounds have a puff of air but less than /p/ in the first of words like pen, pan etc. Is it correct or not?  However, I just listened a word "apple" from a video of Youtube but I can't hear or catch a puff of air from /p/ in apple.  It sounds like /p/ after /s/ like the words spy, spin etc. I've got a dashboard that shows both active and unactivated parts of an app (users opt in to a service). Is there any standard for the best way to show an element/section is unactivated? Any way to encourage activation?    I'm sure there are numerous examples out there of apps that have "can't use this till you pay" section, but I can't seem to find anything that would illuminate a standard practice here.  Thanks!  edit: I'm picking this up from someone else's design. Here's my starting point: If the quotient group $G/N$ be isomorphic to $G_2$, is $G$ isomorphic to $G_1\times G_2$ where $N$ is isomorphic to $G_1$? Noun for "receive"? Receipt?  Receiving?  I'm trying to come up with a name for "the acceptance of a delivery."  I'd like to be able to say      Ten deliveries were made but there are only five [fill_in_the_blank_here] on record.   Any suggestions?