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What is Full Text Search vs LIKE
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MySQL creates an index from the words of the enabled full-text search column and performs searches on this index. MySQL uses a sophisticated algorithm to determine the rows matched against the search query.
Also, from this S...
Is there a REAL performance difference between INT and VARCHAR primary keys?
...e performance difference between using INT vs. VARCHAR as a primary key in MySQL? I'd like to use VARCHAR as the primary key for reference lists (think US States, Country Codes) and a coworker won't budge on the INT AUTO_INCREMENT as a primary key for all tables.
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How to choose the id generation strategy when using JPA and Hibernate
...table. Do not use in a cluster.
identity
supports identity columns in DB2, MySQL, MS SQL Server, Sybase and HypersonicSQL. The returned identifier is of type long, short or int.
sequence
uses a sequence in DB2, PostgreSQL, Oracle, SAP DB, McKoi or a generator in Interbase. The returned identifier is...
Non-recursive depth first search algorithm
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DFS:
list nodes_to_visit = {root};
while( nodes_to_visit isn't empty ) {
currentnode = nodes_to_visit.take_first();
nodes_to_visit.prepend( currentnode.children );
//do something
}
BFS:
list nodes_to_visit = {root};
while( nodes_to_visit isn't ...
My Git repository is in the wrong root directory. Can I move it? (../ instead of ./)
...or so ago I ran the command in the directory one directory higher than the root of my project.
9 Answers
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os.walk without digging into directories below
... os.path.isdir(some_dir)
num_sep = some_dir.count(os.path.sep)
for root, dirs, files in os.walk(some_dir):
yield root, dirs, files
num_sep_this = root.count(os.path.sep)
if num_sep + level <= num_sep_this:
del dirs[:]
It works just like os.walk, but y...
COUNT(*) vs. COUNT(1) vs. COUNT(pk): which is better? [duplicate]
... are using as well as the type of table in some cases.
For example, using MySQL, count(*) will be fast under a MyISAM table but slow under an InnoDB. Under InnoDB you should use count(1) or count(pk).
share
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How do I list all cron jobs for all users?
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You would have to run this as root, but:
for user in $(cut -f1 -d: /etc/passwd); do crontab -u $user -l; done
will loop over each user name listing out their crontab. The crontabs are owned by the respective users so you won't be able to see another u...
List files by last edited date
...ort | cut -f 2- -d ' '
The result looks a lot like ls -l:
-rw-r--r-- 1 root root 3892 08/11/2009 11:03:36 /usr/share/man/man1/xmllint.1.gz
-rw-r--r-- 1 root root 22946 08/13/2009 11:59:20 /usr/share/man/man1/curl.1.gz
-rw-r--r-- 1 root root 728 08/17/2009 12:0...
Sass combining parent using ampersand (&) with type selectors
...his has been possible since Sass 3.3.0.rc.1 (Maptastic Maple).
The @at-root directive causes one or more rules to be emitted at the root of the document, rather than being nested beneath their parent selectors.
We can combine the @at-root directive along with interpolation #{} to arrive at the...