大约有 43,000 项符合查询结果（耗时：0.0348秒） [XML]
What's the difference between session.Merge and session.SaveOrUpdate?
...
if the object is versioned (by a <version> or <timestamp>), and the
version property value is the same value assigned to a newly
instantiated object, save() it
otherwise update() the object
and merge() is very different:
if there is a persistent instance with t...
What are the options for storing hierarchical data in a relational database? [closed]
... thought I'd give Celko a bit of competition by coming up with a method to convert an Adjacency List to Nested sets at speeds that just seem impossible. Here's the performance of the push stack method on my i5 laptop.
Duration for 1,000 Nodes = 00:00:00:870
Duration for 10,000 Nodes = 00:01...
How to change the default collation of a table?
...set and collation of a table including those of existing columns (note the convert to clause):
alter table <some_table> convert to character set utf8mb4 collate utf8mb4_unicode_ci;
Edited the answer, thanks to the prompting of some comments:
Should avoid recommending utf8. It's almost n...
How do I remove duplicates from a C# array?
...sn't an answer. "How do I make pancakes?" "Put some ingredients in a bow and mix."
– Quarkly
Apr 4 at 19:21
1
...
How do you use variables in a simple PostgreSQL script?
For example, in MS-SQL, you can open up a query window and run the following:
10 Answers
...
Visual studio long compilation when replacing int with double
... Omg, Microsoft, you're kidding me... Tnx for help, it's truly MSSE and .Net 4.0+ who are culprits
– Alex Zhukovskiy
Jun 7 '14 at 17:07
...
Occurrences of substring in a string
...at this might or might not return the result expected. With substring "aa" and string to search "aaa" the number of occurences expected may be one (returned by this code), but may be two as well (in this case you'll need "lastIndex++" instead of "lastIndex += findStr.length()") depending on what you...
How to use QueryPerformanceCounter?
...eded to change from using milliseconds to microseconds for my Timer class, and after some research I've decided that QueryPerformanceCounter is probably my safest bet. (The warning on Boost::Posix that it may not works on Win32 API put me off a bit). However, I'm not really sure how to implement i...
Why does sizeof(x++) not increment x?
...
From the C99 Standard (the emphasis is mine)
6.5.3.4/2
The sizeof operator yields the size (in bytes) of its operand, which may be an expression or the parenthesized name of a type. The size is determined from the type of the opera...
Do you need to dispose of objects and set them to null?
Do you need to dispose of objects and set them to null, or will the garbage collector clean them up when they go out of scope?
...