大约有 42,000 项符合查询结果（耗时：0.0622秒） [XML]
What is the optimal length for an email address in a database?
...ail address must not exceed 254 characters. As described in RFC3696 Errata ID 1690.
I got the original part of this information from here
share
|
improve this answer
|
follo...
In Firebase, is there a way to get the number of children of a node without loading all the node dat
...ou gave does indeed load the entire set of data and then counts it client-side, which can be very slow for large amounts of data.
Firebase doesn't currently have a way to count children without loading data, but we do plan to add it.
For now, one solution would be to maintain a counter of the numb...
How to avoid having class data shared among instances?
... def __init__(self):
self.list = []
Declaring the variables inside the class declaration makes them "class" members and not instance members. Declaring them inside the __init__ method makes sure that a new instance of the members is created alongside every new instance of the object, whi...
Javascript How to define multiple variables on a single line?
... So if you change just one of those variables, and wanted them to act individually you will not get what you want because they are not individual objects.
There is also a downside in multiple assignment, in that the secondary variables become globals, and you don't want to leak into the global name...
Mysql: Select rows from a table that are not in another
...o the subselect based on a column name, not *.
For example, if you had an id field common to both tables, you could do:
SELECT * FROM Table1 WHERE id NOT IN (SELECT id FROM Table2)
Refer to the MySQL subquery syntax for more examples.
...
Difference between JSONObject and JSONArray
...
When you are working with JSON data in Android, you would use JSONArray to parse JSON which starts with the array brackets. Arrays in JSON are used to organize a collection of related items (Which could be JSON objects).
For example: [{"name":"item 1"},{"name": "item2...
How to empty/destroy a session in rails?
...sessions (which you should probably use) you can expire through a query: guides.rubyonrails.org/security.html#session-expiry
– m33lky
Feb 24 '12 at 7:14
add a comment
...
C# - Selectively suppress custom Obsolete warnings
...sable:
using System;
class Test
{
[Obsolete("Message")]
static void Foo(string x)
{
}
static void Main(string[] args)
{
#pragma warning disable 0618
// This one is okay
Foo("Good");
#pragma warning restore 0618
// This call is bad
Foo("Bad"...
DefaultInlineConstraintResolver Error in WebAPI 2
...(DoubleRouteConstraint) },
{ "float", typeof(FloatRouteConstraint) },
{ "guid", typeof(GuidRouteConstraint) },
{ "int", typeof(IntRouteConstraint) },
{ "long", typeof(LongRouteConstraint) },
// Length constraints
{ "minlength", typeof(MinLengthRouteConstraint) },
{ "maxlength", typeof(MaxLengthRout...
Multi-project test dependencies with gradle
...ts is no longer a public property of a project.
– David Pärsson
Jan 14 '13 at 10:39
3
...