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How do I check OS with a preprocessor directive?
...eturn a name of platform, if determined, otherwise - an empty string
const char *get_platform_name() {
return (PLATFORM_NAME == NULL) ? "" : PLATFORM_NAME;
}
int main(int argc, char *argv[]) {
puts(get_platform_name());
return 0;
}
Tested with GCC and clang on:
Debian 8
Windows (Min...
Do the JSON keys have to be surrounded by quotes?
...ins and ends with
quotation marks. [...]
string = quotation-mark *char quotation-mark
quotation-mark = %x22 ; "
Read the whole RFC here.
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How to create relationships in MySQL
...s defined as the default storage engine,can check using command (mysql> SELECT @@default_storage_engine;)
– Arun
Feb 18 at 4:00
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Ordering by the order of values in a SQL IN() clause
...
Use MySQL's FIELD() function:
SELECT name, description, ...
FROM ...
WHERE id IN([ids, any order])
ORDER BY FIELD(id, [ids in order])
FIELD() will return the index of the first parameter that is equal to the first parameter (other than the first paramet...
An explicit value for the identity column in table can only be specified when a column list is used
...tead of
SET IDENTITY_INSERT archive_table ON;
INSERT INTO archive_table
SELECT *
FROM source_table;
SET IDENTITY_INSERT archive_table OFF;
you need to write
SET IDENTITY_INSERT archive_table ON;
INSERT INTO archive_table (field1, field2, ...)
SELECT field1, field2, ...
FROM source_table;...
MySQL: Fastest way to count number of rows
...s.
The solution is SQL_CALC_FOUND_ROWS. This is usually used when you are selecting rows but still need to know the total row count (for example, for paging).
When you select data rows, just append the SQL_CALC_FOUND_ROWS keyword after SELECT:
SELECT SQL_CALC_FOUND_ROWS [needed fields or *] FROM t...
maximum value of int
...< (sizeof(x) * 8 - 1)))
int a = SIGNED_MAX(a);
long b = SIGNED_MAX(b);
char c = SIGNED_MAX(c); /* if char is signed for this target */
short d = SIGNED_MAX(d);
long long e = SIGNED_MAX(e);
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How to find out line-endings in a text file?
...
Unfortunately, I don't think vi can show those specific characters. You can try od -c <filename> which I believe will display \n or \r\n.
– Ryan Berger
Aug 25 '10 at 22:51
...
Getting a list of files in a directory with a glob
...ing like that.
NSMutableArray* files = [NSMutableArray array];
glob_t gt;
char* pattern = "/bin/*";
if (glob(pattern, 0, NULL, &gt) == 0) {
int i;
for (i=0; i<gt.gl_matchc; i++) {
[files addObject: [NSString stringWithCString: gt.gl_pathv[i]]];
}
}
globfree(&gt);
retu...
How can foreign key constraints be temporarily disabled using T-SQL?
...use this script to list the constraint status. Will be very helpfull:
SELECT (CASE
WHEN OBJECTPROPERTY(CONSTID, 'CNSTISDISABLED') = 0 THEN 'ENABLED'
ELSE 'DISABLED'
END) AS STATUS,
OBJECT_NAME(CONSTID) AS CONSTRAINT_NAME,
OBJECT_NAME(FKEYID) AS TABLE_NAM...