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MySQL check if a table exists without throwing an exception
...PDO syntax for it, but this seems pretty straight-forward:
$result = mysql_query("SHOW TABLES LIKE 'myTable'");
$tableExists = mysql_num_rows($result) > 0;
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...
Adding a cross-reference to a subheading or anchor in another page
... general :ref: directive, documented here. They give this example:
.. _my-reference-label:
Section to cross-reference
--------------------------
This is the text of the section.
It refers to the section itself, see :ref:`my-reference-label`.
Although the general hyperlinkin...
#1071 - Specified key was too long; max key length is 1000 bytes
...per column as you define the index. For example:
...
KEY `index` (`parent_menu_id`,`menu_link`(50),`plugin`(50),`alias`(50))
...
But what's the best prefix length for a given column? Here's a method to find out:
SELECT
ROUND(SUM(LENGTH(`menu_link`)<10)*100/COUNT(`menu_link`),2) AS pct_leng...
Skip certain tables with mysqldump
...!/bin/bash
PASSWORD=XXXXXX
HOST=XXXXXX
USER=XXXXXX
DATABASE=databasename
DB_FILE=dump.sql
EXCLUDED_TABLES=(
table1
table2
table3
table4
tableN
)
IGNORED_TABLES_STRING=''
for TABLE in "${EXCLUDED_TABLES[@]}"
do :
IGNORED_TABLES_STRING+=" --ignore-table=${DATABASE}.${TABLE}"
done
echo "Dump st...
How do I use installed packages in PyCharm?
...ere you can import the module.
>> import gnuradio
>> gnuradio.__file__
"path/to/gnuradio"
Most commonly you'll have a folder structure like this:
foobarbaz/
gnuradio/
__init__.py
other_file.py
You want to add foobarbaz to the path here.
...
Iterating C++ vector from the end to the beginning
...
The best way is:
for (vector<my_class>::reverse_iterator i = my_vector.rbegin();
i != my_vector.rend(); ++i ) {
}
rbegin()/rend() were especially designed for that purpose. (And yes, incrementing a reverse_interator moves it backward.)
Now...
Does C# have extension properties?
...{
private static readonly ConditionalWeakTable<Person, Employee> _employees =
new ConditionalWeakTable<Person, Employee>();
public decimal Salary
{
get
{
// `this` is the instance of Person
return _employees.GetOrCreate(this...
How to check for null in Twig?
... Notice: as Twig 2.x check for variable is equal to value like is_ sameas must be {% if var is same as(false) %} not {% if var is sameas(false) %} see Doc url => twig.symfony.com/doc/2.x/tests/sameas.html
– ahmed hamdy
Jul 15 '19 at 17:01
...
Why does changing 0.1f to 0 slow down performance by 10x?
...Here's the test code compiled on x64:
int main() {
double start = omp_get_wtime();
const float x[16]={1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9,2.0,2.1,2.2,2.3,2.4,2.5,2.6};
const float z[16]={1.123,1.234,1.345,156.467,1.578,1.689,1.790,1.812,1.923,2.034,2.145,2.256,2.367,2.478,2.589,2.690}...
Reading specific lines only
...
with linecache.getlin('some_file', 4) I get the 4th line, not the 5th.
– Juan
Dec 11 '14 at 18:14
...