大约有 37,000 项符合查询结果（耗时：0.0262秒） [XML]
Preventing Laravel adding multiple records to a pivot table
...in the array. This way, only the id's given in the array will exist in the table. Brilliant @Barryvdh uses an undocumented second parameter to disable that detaching, so no relationships not in the given array are deleted but only unique id's will be attached. Check out the "syncing for convienence"...
Why would anyone use set instead of unordered_set?
... and many other places. What I understand is that unordered_set is hash table with O(1) lookup complexity. On the other hand, set is nothing but a tree with log(n) lookup complexity. Why on earth would anyone use set instead of unordered_set? i.e is there a need for set anymore?
...
What are database normal forms and can you give examples? [closed]
...y normalization, which is a process of organizing columns (attributes) and tables (relations) to reduce data redundancy and improve data integrity. (as written on Wikipedia ).
...
REST URI convention - Singular or plural name of resource while creating it
...from our database schema. And database standards tend to advocate singular table names, so we're going with that, but still under the same logic as this answer.
– André C. Andersen
Nov 24 '17 at 12:01
...
How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?
So if I have to choose between a hash table or a prefix tree what are the discriminating factors that would lead me to choose one over the other. From my own naive point of view it seems as though using a trie has some extra overhead since it isn't stored as an array but that in terms of run time (a...
Best way to get identity of inserted row?
...
@@IDENTITY returns the last identity value generated for any table in the current session, across all scopes. You need to be careful here, since it's across scopes. You could get a value from a trigger, instead of your current statement.
SCOPE_IDENTITY() returns the last identity val...
Insert multiple rows WITHOUT repeating the “INSERT INTO …” part of the statement?
...
INSERT INTO dbo.MyTable (ID, Name)
SELECT 123, 'Timmy'
UNION ALL
SELECT 124, 'Jonny'
UNION ALL
SELECT 125, 'Sally'
For SQL Server 2008, can do it in one VALUES clause exactly as per the statement in your question (you just need to add a comm...
How do I make a column unique and index it in a Ruby on Rails migration?
... What is the best way to do it? Also is there a way to index a column in a table?
8 Answers
...
Entity Framework Code First - two Foreign Keys from same table
...his answer, however it makes the Foreign Key columns nullable in the Match table.
– RobHurd
Aug 21 '16 at 14:41
This w...
Postgresql SELECT if string contains
...Concatenate using '||' with the literal percent signs:
SELECT id FROM TAG_TABLE WHERE 'aaaaaaaa' LIKE '%' || tag_name || '%';
share
|
improve this answer
|
follow
...