大约有 6,000 项符合查询结果（耗时：0.0205秒） [XML]
Postgres unique constraint vs index
..., btree (con_id)
"master_unique_idx" UNIQUE, btree (ind_id)
In table description (\d in psql) you can tell unique constraint from unique index.
Uniqueness
Let's check uniqueness, just in case.
test=# insert into master values (0, 0);
INSERT 0 1
test=# insert into master values (0, 1);
ERROR...
Regular expression for a hexadecimal number?
...
If you're using Perl or PHP, you can replace
[0-9a-fA-F]
with:
[[:xdigit:]]
share
|
improve this answer
|
follow
...
What in the world are Spring beans?
...ne who isn't used to Spring, I think Wikipedia Spring's article has a nice description:
Central to the Spring Framework is its inversion of control container,
which provides a consistent means of configuring and managing Java
objects using reflection. The container is responsible for managin...
Best practice using NSLocalizedString
...ningless all-caps string with a module-specific prefix, and a very precise description:
NSLocalizedString(@"DOWNLOAD_CANCEL_OR_CONTINUE", @"Cancel notice window title when a download takes too long to proceed");
Using the same string in different places
If you use the same string multiple times,...
How to display Base64 images in HTML?
...
If you have PHP on the back-end, you can use this code:
$image = 'http://images.itracki.com/2011/06/favicon.png';
// Read image path, convert to base64 encoding
$imageData = base64_encode(file_get_contents($image));
// Format the image...
Replace a newline in TSQL
...ted, here's the code.
-- =============================================
-- Description: TRIMs a string 'for real' - removes standard whitespace from ends,
-- and replaces ASCII-char's 9-13, which are tab, line-feed, vert tab,
-- form-feed, & carriage-return (respectively), with a whitespace
-- (...
Why can I add named properties to an array as if it were an object?
...call a "bug" can as well be an awesome "feature". You can add a tittle and description to arrays without affecting their contents or length and without having to wrap them in objects with title, description and items properties. It all depends on how well you know the language and how you use it.
...
typecast string to integer - Postgres
...ing into an integer.
Solution
Create a user-defined function inspired by PHP's intval() function.
CREATE FUNCTION intval(character varying) RETURNS integer AS $$
SELECT
CASE
WHEN length(btrim(regexp_replace($1, '[^0-9]', '','g')))>0 THEN btrim(regexp_replace($1, '[^0-9]', '','g'))::intege...
How to generate a random number in C++?
...hat sequence - it should look random.
EDIT:
Oh I get it.
Apparently verbal description is not enough (maybe language barrier or something... :) ).
OK.
Old-fashioned C code example based on the same srand()/rand()/time() functions that was used in the question:
#include <stdlib.h>
#include <...
Orchestration vs. Choreography
...ervice composition.
Service Choreography
Service choreography is a global description of the participating services, which is defined by exchange of messages, rules of interaction and agreements between two or more endpoints. Choreography employs a decentralized approach for service composition.
T...