大约有 37,000 项符合查询结果（耗时：0.0263秒） [XML]
Most popular screen sizes/resolutions on Android phones [closed]
...
You can see the resolutions for those categories in the Table 2, in this section: http://developer.android.com/guide/practices/screens_support.html#testing
share
|
improve this an...
MYSQL OR vs IN performance
...s the same.
$t = microtime(true);
for($i=0; $i<10000; $i++):
$q = DB::table('users')->where('id',1)
->orWhere('id',2)
->orWhere('id',3)
->orWhere('id',4)
->orWhere('id',5)
->orWhere('id',6)
->orWhere('id',7)
->orWhere('id',8)
->orWhere(...
Are foreign keys really necessary in a database design?
... code using things like ON DELETE CASCADE. This means that if you have one table containing users and another containing orders or something, then deleting a user could automatically delete all orders that point to that user.
...
What is the use of the @Temporal annotation in Hibernate?
...on and you want to store precise date/time or both (TIMESTAMP) in database table.
The temporal precision is not specified in core Java APIs. @Temporal is a JPA annotation that converts back and forth between timestamp and java.util.Date. It also converts time-stamp into time. For example, in the s...
Laravel Eloquent ORM Transactions
...ging this.
After reading THIS stackoverflow answer, I realized my database tables were using MyISAM instead of InnoDB.
For transactions to work on Laravel (or anywhere else as it seems), it is required that your tables are set to use InnoDB
Why?
Quoting MySQL Transactions and Atomic Operations docs ...
How to execute raw SQL in Flask-SQLAlchemy app
...e their own execute method:
result = db.session.execute('SELECT * FROM my_table WHERE my_column = :val', {'val': 5})
All your application queries should be going through a session object, whether they're raw SQL or not. This ensures that the queries are properly managed by a transaction, which al...
How to draw a circle with text in the middle?
...can make border-radius:50%; that makes your code event more elegant and portable, without having to change this attribute each time based on the width and height ;)
– bonCodigo
Aug 14 '14 at 10:37
...
Convert light frequency to RGB?
...rmilab article makes the important point that some colours are not representable in RGB (bright oranges being a good example) because you cannot "make" arbitrary colours of light by adding three primary colours together, whatever our physics teachers may have told us (well mine did). Too bad, but in...
How to get the max of two values in MySQL?
...ll. E.g. select greatest(date1, ifnull(date2, "0000-00-00 00.00:00")) from table1 where date2 is null; will get you date1.
– Christoph Grimmer-Dietrich
Nov 5 '14 at 14:24
1
...
Host 'xxx.xx.xxx.xxx' is not allowed to connect to this MySQL server
...you cannot figure out why you get
Access denied, remove from the user
table all entries that have Host
values containing wildcards (entries
that contain '%' or '_' characters). A
very common error is to insert a new
entry with Host='%' and
User='some_user', thinking that this
allows...