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ALTER TABLE without locking the table?
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And have a thorough test plan before swapping. If it fails, start over.
– dkretz
Jan 21 '09 at 2:29
2
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Crontab Day of the Week syntax
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0 and 7 both stand for Sunday, you can use the one you want, so writing 0-6 or 1-7 has the same result.
Also, as suggested by @Henrik, it is possible to replace numbers by shortened name of days, such as MON, THU, etc:
0 - Su...
How to create a new language for use in Visual Studio
I want to write a new templating language, and I want Visual Studio to "support" it. What I need to know is:
7 Answers
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UIDevice uniqueIdentifier deprecated - What to do now?
...ght that the UIDevice uniqueIdentifier property is deprecated in iOS 5 and unavailable in iOS 7 and above. No alternative method or property appears to be available or forthcoming.
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PostgreSQL query to return results as a comma separated list
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You can use the array() and array_to_string() functions togetter with your query.
With SELECT array( SELECT id FROM table ); you will get a result like: {1,2,3,4,5,6}
Then, if you wish to remove the {} signs, you can just use the array_to_string() ...
Does the ternary operator exist in R?
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As if is function in R and returns the latest evaluation, if-else is equivalent to ?:.
> a <- 1
> x <- if(a==1) 1 else 2
> x
[1] 1
> x <- if(a==2) 1 else 2
> x
[1] 2
The power of R is vectorization. The vectorization of t...
How do I combine two data frames?
I'm using Pandas data frames. I have a initial data frame, say D . I extract two data frames from it like this:
6 Answers
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How to generate a Dockerfile from an image?
... -sV=1.36 nginx:latest
It will pull the target docker image automaticlaly and export Dockerfile. Parameter -sV=1.36 is not always required.
Reference: https://hub.docker.com/repository/docker/alpine/dfimage
below is the old answer, it doesn't work any more.
$ docker pull centurylink/dockerfile-from...
How to fix the “java.security.cert.CertificateException: No subject alternative names present” error
...ance("SSL");
sc.init(null, trustAllCerts, new java.security.SecureRandom());
HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
// Create all-trusting host name verifier
HostnameVerifier allHostsValid = new HostnameVerifier() {
public b...
How to link to part of the same document in Markdown?
I am writing a large Markdown document and would like to place a table of contents of sorts at the beginning that will provide links to various locations in the document. How can I do this?
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