大约有 43,000 项符合查询结果(耗时:0.0590秒) [XML]

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Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?

In multiple courses, books, and jobs, I have seen text fields defined as VARCHAR(255) as kind of the default for "shortish" text. Is there any good reason that a length of 255 is chosen so often, other than being a nice round number ? Is it a holdout from some time in the past when there was a go...
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PHP Composer update “cannot allocate memory” error (using Laravel 4)

... can fix the issue. Also you should be committing your composer.lock file and doing a composer install on a production environment which is less resource intensive. More details here: https://github.com/composer/composer/issues/1898#issuecomment-23453850 ...
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error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)' — Miss

...ing to run mysql without passwords turned on... but whenever I ran the command 44 Answers ...
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How to find Unused Amazon EC2 Security groups

...'m try to find a way to determine orphan security groups so I can clean up and get rid of them. Does anyone know of a way to discover unused security groups. ...
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How to load JAR files dynamically at Runtime?

...t classes are in what jars. As opposed to just loading a directory of jars and then instantiating classes. I am misunderstanding it? – Allain Lalonde Sep 13 '08 at 19:13 10 ...
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How to go back in Eclipse?

...'m jumping around a big project following the execution flow (ctrl + click and etc.), is there a way to retrace a step? If my code calls a method and I go to the method definition, is there a key combination that will take me back to the calling code? ...
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Installing Java 7 on Ubuntu

... like to install java manually. I placed the folder of the JDK on the desk and I set environment variables (PATH, CLASSPATH and JAVA_HOME). From the terminal, if I type java -version I get printed ...
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How can I delete multiple lines in vi?

... Sounds like you're entering the commands in command mode (aka. "Ex mode"). In that context :5d would remove line number 5, nothing else. For 5dd to work as intended -- that is, remove five consequent lines starting at the cursor -- enter it in normal mode and d...
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Efficient way to apply multiple filters to pandas DataFrame or Series

I have a scenario where a user wants to apply several filters to a Pandas DataFrame or Series object. Essentially, I want to efficiently chain a bunch of filtering (comparison operations) together that are specified at run-time by the user. ...
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How to get all files under a specific directory in MATLAB?

I need to get all those files under D:\dic and loop over them to further process individually. 8 Answers ...