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Difference between float and decimal data type
...0,2), b float);
mysql> insert into numbers values (100, 100);
mysql> select @a := (a/3), @b := (b/3), @a * 3, @b * 3 from numbers \G
*************************** 1. row ***************************
@a := (a/3): 33.333333333
@b := (b/3): 33.333333333333
@a + @a + @a: 99.9999999990000000000000...
Are soft deletes a good idea? [duplicate]
... is RIGHT
4) The complexities of soft delete never ever stops at a simple select.
A) Suppose you had a UNIQUE constraint. Now you soft-delete a row but the column with UNIQUE constraint is still there. When you want to add the same data back in, you cannot do that without additional "tricks".
B...
Easy interview question got harder: given numbers 1..100, find the missing number(s) given exactly k
...
+1; I've tried the formula in Maple for select numbers and it works. I still couldn't convince myself WHY it works, though.
– polygenelubricants
Aug 16 '10 at 11:12
...
JSF backing bean structure (best practices)
...VC design pattern. The typical use case is supplying an ArrayList to JSF h:selectOneMenu drop-down lists that appear in more than one JSF view. If the data in the dropdown lists is particular to the user, then the bean would be kept in session scope. However, if the data applies to all users (such a...
How do you effectively model inheritance in a database?
...etimes needed, when you want to load a list of all records (without doing select on each and every child table). One way to handle this, is to have one column representing the type of the child class (similar to the rowType field in the TPH), so mixing the TPT and TPH somehow.
Say we want to des...
How to add texture to fill colors in ggplot2
... draw textured rectangles and bars with ggplot2.
# Image/pattern randomly selected from README
path_image <- "http://www.hypergridbusiness.com/wp-content/uploads/2012/12/rocks2-256.jpg"
library(ggplot2)
# devtools::install_github("clauswilke/ggtextures")
ggplot(mtcars, aes(cyl, mpg)) +
ggtex...
Why JavaScript rather than a standard browser virtual machine?
...loping fast.
JavaScript is an ugly language, but through careful use of a selective subset of features, and support from suitable object libraries, it can generally be made fairly tolerable. It seems incremental, practical additions to JavaScript are the only way web scripting is likely to move on....
Best practices for SQL varchar column length [closed]
...hen you need to worry about it and make them smaller. But if you only ever select 1 row from that table, then you can just make them all 255 and it won't matter.
See: What are the optimum varchar sizes for MySQL?
share
...
Null vs. False vs. 0 in PHP
...mpatibility). Despite the design wishing some consistency (outlined in the selected answer here), it all get confusing when you consider method returns that use false/null in not-so-easy to reason ways.
You will often see null being used when they are already using false for something. e.g. filter_i...
How can I tell if a DOM element is visible in the current viewport?
... old answer is very slow, not accurate and has several bugs.
The solution selected as correct is almost never precise. You can read more about its bugs.
This solution was tested on Internet Explorer 7 (and later), iOS 5 (and later) Safari, Android 2.0 (Eclair) and later, BlackBerry, Opera Mob...