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Why can Java Collections not directly store Primitives types?
...tion of primitives. Even in the few cases where I might have wanted to the extra time and space costs of using the reference objects has been negligible. In particular I find that many people think they want Map<int,T>, forgetting that an array will do that trick very nicely.
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Are there disadvantages to using a generic varchar(255) for all text-based fields?
... (If you're wondering, it's this way because Ruby on Rails migrations map String fields to VARCHAR(255) by default and I never bothered to override it).
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Equals(=) vs. LIKE
... these operators!
= is a comparison operator that operates on numbers and strings. When comparing strings, the comparison operator compares whole strings.
LIKE is a string operator that compares character by character.
To complicate matters, both operators use a collation which can have important...
Group query results by month and year in postgresql
...ht make sense to use date_trunc, but in some cases having a formatted date string is preferable, and if you're using a performant data warehouse the additional computation might not be a deal breaker. For example, if you are running a quick analytics report using redshift, and it usually takes 3 sec...
How to persist a property of type List in JPA?
... should anyone be looking for an alternative solution where you store your string lists as one field in your database, here's how I solved that. Create a Converter like this:
import java.util.Arrays;
import java.util.List;
import javax.persistence.AttributeConverter;
import javax.persistence.Conve...
Please explain the exec() function and its family
... family have different behaviours:
l : arguments are passed as a list of strings to the main()
v : arguments are passed as an array of strings to the main()
p : path/s to search for the new running program
e : the environment can be specified by the caller
You can mix them, therefore you have:
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How to convert DateTime to VarChar
...DECLARE @myDateTime DATETIME
SET @myDateTime = '2008-05-03'
--
-- Convert string
--
SELECT LEFT(CONVERT(VARCHAR, @myDateTime, 120), 10)
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How to find memory leak in a C++ code/project?
...you allocated:
char* str = new char [30]; // Allocate 30 bytes to house a string.
delete [] str; // Clear those 30 bytes and make str point nowhere.
2
Reallocate memory only if you've deleted. In the code below, str acquires a new address with the second allocation. The first address is lost ir...
Fastest way to remove first char in a String
Say we have the following string
4 Answers
4
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Where in memory are my variables stored in C?
...t; data (correct)
constant data types -----> code and/or data. Consider string literals for a situation when a constant itself would be stored in the data segment, and references to it would be embedded in the code
local variables(declared and defined in functions) --------> stack (correct)
va...