大约有 1,948 项符合查询结果（耗时：0.0132秒） [XML]
Can someone explain in simple terms to me what a directed acyclic graph is?
... Andriyev, +1 for the deadlock example. This is in fact used by MySQL's InnoDB engine, and they call it a "wait-for-graph", as in, "that row has to wait for the lock on that row to be released"
– Roland Bouman
Feb 17 '10 at 19:40
...
How to do an update + join in PostgreSQL?
...
coming from mysql it's unintuitive that the same join used for select won't also update just by adding a set phrase :( still - the syntax for this is probably easier for a newcomer to sql to master.
– WEBjuju
...
How do I create a URL shortener?
...Take an auto-generated, unique numerical key (the auto-incremented id of a MySQL table for example).
For this example, I will use 12510 (125 with a base of 10).
Now you have to convert 12510 to X62 (base 62).
12510 = 2×621 + 1×620 = [2,1]
This requires the use of integer division and modulo. A ...
How to use greater than operator with date?
...
It bears noting that MySQL seems a bit picky about the date format; while either 2019/02/08 21:04:07 or 2019-02-08 21:04:07 produces the expected outcome, 02-08-2019 21:04:07, using the US date format, casts a much wider net.
...
file_put_contents - failed to open stream: Permission denied
...ld now, but there's no need to manually write queries to a file like this. MySQL has logging support built in, you just need to enable it within your dev environment.
Take a look at the documentation for the 'general query log':
http://dev.mysql.com/doc/refman/5.1/en/query-log.html
...
Does Django scale? [closed]
...ormance as the load increases.
We're using Apache front-ending Django and MySQL. The OS is Red Hat Enterprise Linux (RHEL). 64-bit. We use mod_wsgi in daemon mode for Django. We've done no cache or database optimization other than to accept the defaults.
We're all in one VM on a 64-bit Dell ...
What's the difference between session.Merge and session.SaveOrUpdate?
...e.class);
configuration.setProperty("connection.driver_class","com.mysql.jdbc.Driver");
configuration.setProperty("hibernate.connection.url", "jdbc:mysql://localhost:3306/hibernate");
configuration.setProperty("hibernate.connection.username", "...
How to integrate nodeJS + Socket.IO and PHP?
... just have an author and message, and when you press send it is saved in a mysql database. The idea is to send real time updates, and have a real conversation. ;) We'll use nodeJS for that.
I won't talk about PHP code, it is really simple and not interesting here; what I want to show you is how to ...
Is it possible to insert multiple rows at a time in an SQLite database?
In MySQL you can insert multiple rows like this:
24 Answers
24
...
How to generate a new Guid in stored procedure?
...
In MySQL it is UUID().
so the query would be:
insert into cars
(id, Make, Model)
values(UUID(), "Ford", "Mustang")
if you want to reuse the uuid you can do it like this:
set @id=UUID();
insert into cars
(id, Make, Model)
val...