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selecting unique values from a column
I have a MySQL table which contains the following type of information:
9 Answers
9
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Efficiency of purely functional programming
...n pure lambda calculus) is known, even with laziness.
The aforementioned union-find
Hash tables
Arrays
Some graph algorithms
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However, we assume that in "imperative" languages access to memory is O(1) whereas in theory that can't be so asymptotically (i.e. for unbounded problem sizes) and acc...
How to change the CHARACTER SET (and COLLATION) throughout a database?
Our previous programmer set the wrong collation in a table (Mysql). He set it up with Latin collation, when it should be UTF8, and now I have issues. Every record with Chinese and Japan character turn to ??? character.
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XMLHttpRequest cannot load file. Cross origin requests are only supported for HTTP
... wamp? I am running wamp and still receiving this message. Apache, php and mysql are all up-to-date
– user2883071
Dec 24 '14 at 18:52
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B-Tree vs Hash Table
In MySQL, an index type is a b-tree, and access an element in a b-tree is in logarithmic amortized time O(log(n)) .
5 Answ...
NoSQL - MongoDB vs CouchDB [closed]
...ch, filling up disks.
For example: For most things that you would do with MySQL or PostgreSQL, but having predefined columns really holds you back.
CouchDB (1.2)
Written in: Erlang
Main point: DB consistency, ease of use
License: Apache
Protocol: HTTP/REST
Bi-directional (!) replication,
continu...
Cannot change column used in a foreign key constraint
... DELETE ) will wait till timeout or UNLOCK TABLES; is executed
http://dev.mysql.com/doc/refman/5.5/en/lock-tables.html
EDIT 2: OP asked for a more detailed explanation of the line "The type and definition of foreign key field and reference must be equal. This means your foreign key disallows chang...
What does the KEY keyword mean?
In this MySQL table definition:
2 Answers
2
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Laravel Schema onDelete set null
...cument what options there are, but I think you can assume it's the default mysql values (see ../ vendor / laravel / framework / src / Illuminate / Database / Schema / Grammars / Grammar.php)
– Dirk Jan
Mar 23 at 14:47
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Why use sprintf function in PHP?
...example, forcing 2dp, 4-digit numbers, etc. It's quite useful for building MySQL query strings.
Another advantage is that it allows you to separate the layout of the string from the data being fed into it, almost like feeding in paramaters. For example, in the case of a MySQL query:
// For securit...