大约有 40,000 项符合查询结果（耗时：0.0653秒） [XML]
Should I use px or rem value units in my CSS? [closed]
...size of a pixel on a 96 dpi display. On a display that has a dpi substantially different than 96dpi (like Retina displays), the user agent rescales the px unit so that its size matches that of a reference pixel. In other words, this rescaling is exactly why 1 CSS pixel equals 2 physical Retina dis...
Rails migrations: self.up and self.down versus change
... For example, in your case what is the reverse operation of add_column to call when you rollback? Of course it's remove_column. What is the inverse of create_table? It's drop_table. So in these cases rails know how to rollback and define a down method is superfluous (you can see in the documentation...
How to hide databases that I am not allowed to access
... I connect to my Heroku - Postgresql database via pgAdmin3 , It lists all the tables (about 2600). Every time I open the pgAdmin3 I have to find my own database.
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An efficient compression algorithm for short text strings [closed]
I'm searching for an algorithm to compress small text strings: 50-1000 bytes (i.e. URLs). Which algorithm works best for this?
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Right query to get the current number of connections in a PostgreSQL DB
...ence.
Both queries are based on exactly the same data, so they will be equally accurate.
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DateTime2 vs DateTime in SQL Server
...e seconds precision.
datetimeoffset provides time zone
support for globally deployed
applications.
datetime2 has larger date range, a larger default fractional precision, and optional user-specified precision. Also depending on the user-specified precision it may use less storage.
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How to create a database from shell command?
...for something like createdb in PostgreSQL or any other solution that would allow me to create database with a help of a shell command. Any hints?
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Difference between Select Unique and Select Distinct
... database brands other than Oracle, SELECT UNIQUE may not be recognized at all.
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About Python's built in sort() method
...mergesort that's still used in Java, and one can hope that Java will eventually switch to his recent port of timsort).
Some explanation of the Java port of timsort is here, the diff is here (with pointers to all needed files), the key file is here -- FWIW, while I'm a better C programmer than Java ...
In C#, how do I calculate someone's age based on a DateTime type birthday?
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This answer does not work with all locales and all ages. Several countries have skipped dates after the birth of current living people, including Russia (1918), Greece (1924) and Turkey (1926).
– Lars D
Nov 9 '09 at 2...