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“Insert if not exists” statement in SQLite
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If you have a table called memos that has two columns id and text you should be able to do like this:
INSERT INTO memos(id,text)
SELECT 5, 'text to insert'
WHERE NOT EXISTS(SELECT 1 FROM memos WHERE id = 5 AND text = 'text to insert');
If a record already contains a row where ...
Getting a better understanding of callback functions in JavaScript
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Why do you cast callback to string and then check its type? Will this enhance performance? This is like checking the type, checking if the converted boolean returns true and then checking its type again and testing it against the string... Could you exp...
find vs find_by vs where
...is used as a helper when you're searching for information within a column, and it maps to such with naming conventions. For instance, if you have a column named name in your database, you'd use the following syntax:
Model.find_by(name: "Bob")
.where is more of a catch all that lets you use a bit...
Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.
...SQL views, Hibernate docs write:
There is no difference between a view and a base table for a Hibernate mapping. This is transparent at the database level
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How do you express binary literals in Python?
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This is interesting for when you have strings, but if working with pure numbers, you add unnecessary computations to the code.
– Daniel Möller
Aug 18 '17 at 17:34
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For each row return the column name of the largest value
I have a roster of employees, and I need to know at what department they are in most often. It is trivial to tabulate employee ID against department name, but it is trickier to return the department name, rather than the number of roster counts, from the frequency table. A simple example below (colu...
Why #egg=foo when pip-installing from git repo
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per pip install -h the "egg" string is the directory that gets checked out as part of the install
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Format bytes to kilobytes, megabytes, gigabytes
...es($bytes, $force_unit = NULL, $format = NULL, $si = TRUE)
{
// Format string
$format = ($format === NULL) ? '%01.2f %s' : (string) $format;
// IEC prefixes (binary)
if ($si == FALSE OR strpos($force_unit, 'i') !== FALSE)
{
$units = array('B', 'KiB', 'MiB', 'GiB', 'TiB',...
How to reset or change the MySQL root password?
...lumn doesn't exist, you may want to try:
UPDATE user SET authentication_string=password('YOURNEWPASSWORD') WHERE user='root';
Note: This method is not regarded as the most secure way of resetting the password, however, it works.
References:
Set / Change / Reset the MySQL root password on Ubu...
PHP + curl, HTTP POST sample code?
... CURLOPT_RETURNTRANSFER means that curl_exec will return the response as a string rather than outputting it.
– bnp887
Dec 28 '16 at 14:27
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