大约有 40,000 项符合查询结果（耗时：0.0299秒） [XML]
Data structure: insert, remove, contains, get random element, all at O(1)
...
Consider a data structure composed of a hashtable H and an array A. The hashtable keys are the elements in the data structure, and the values are their positions in the array.
insert(value): append the value to array and let i be its index in A. Set H[value]=i.
remov...
Do I need to create indexes on foreign keys on Oracle?
I have a table A and a table B . A has a foreign key to B on B 's primary key, B_ID .
7 Answers
...
When to use a View instead of a Table?
When should a View actually be used over an actual Table? What gains should I expect this to produce?
8 Answers
...
Why do you create a View in a database?
...ews can hide complexity
If you have a query that requires joining several tables, or has complex logic or calculations, you can code all that logic into a view, then select from the view just like you would a table.
2. Views can be used as a security mechanism
A view can select certain columns an...
Use numpy array in shared memory for multiprocessing
... function G inside of F which references V?
– Coffee_Table
Oct 27 '17 at 1:38
5
Warning: This ans...
CUDA incompatible with my gcc version
...l directory and then make symbolic links to the supported gcc version executables. Pass that local directory to nvcc via the --compiler-bindir option, and you should be able to compile CUDA code without affecting the rest of your system.
EDIT:
Note that this question, and answer, pertain to CUDA...
Sqlite primary key on multiple columns
...
According to the documentation, it's
CREATE TABLE something (
column1,
column2,
column3,
PRIMARY KEY (column1, column2)
);
share
|
improve this answer
...
Find difference between timestamps in seconds in PostgreSQL
I have a table in PostgreSQL 8.3 with 2 timestamp columns. I would like to get the difference between these timestamps in seconds. Could you please help me how to get this done?
...
Vertically centering a div inside another div [duplicate]
...
tl;dr
Vertical align middle works, but you will have to use table-cell on your parent element and inline-block on the child.
This solution is not going to work in IE6 & 7. Yours is the safer way to go for those. But since you tagged your question with CSS3 and HTML5 I was thinkin...
Meaning of Open hashing and Closed hashing
... us the index (aka. address) at which an object will be stored in the hash table is not completely determined by its hash code. Instead, the index may vary depending on what's already in the hash table.
The "closed" in "closed hashing" refers to the fact that we never leave the hash table; every...