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How do I check if an index exists on a table field in MySQL?
...Use SHOW INDEX like so:
SHOW INDEX FROM [tablename]
Docs: https://dev.mysql.com/doc/refman/5.0/en/show-index.html
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关于php的socket初探 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...些多路复用的模式中，异步阻塞/非阻塞模式的扩展性和性能最好。
引入阻塞/非阻塞,、同步/异步比喻很形象的一段话：
有A，B，C，D四个人在钓鱼：
A用的是最老式的鱼竿，所以呢，得一直守着，等到鱼上钩了再拉杆；
B的...
IEnumerable vs List - What to Use? How do they work?
... and possibly optimize the program. Remember how LINQ doesn't generate the SQL to query the database until you enumerate it? Consider this:
public IEnumerable<Animals> AllSpotted()
{
return from a in Zoo.Animals
where a.coat.HasSpots == true
select a;
}
public IEnum...
How do I select an entire row which has the largest ID in the table?
...ow profiles and it appears our solutions have the same performance using MySQL. For my own knowledge, do you know what DBMS has poorer performance for subselects?
– unutbu
Feb 7 '14 at 20:08
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What does collation mean?
What does collation mean in SQL, and what does it do?
9 Answers
9
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How to add 'ON DELETE CASCADE' in ALTER TABLE statement
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Just tested in SqlServer, but possible you have to chance go with semi-colon as in postgres and SqlServer itself. But the remain core codes are sql standar. Test with semi-colons, I just changed it
– David Silva-Barrer...
Why shouldn't I use mysql_* functions in PHP?
What are the technical reasons for why one shouldn't use mysql_* functions? (e.g. mysql_query() , mysql_connect() or mysql_real_escape_string() )?
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Limiting the number of records from mysqldump?
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As skaffman says, use the --where option:
mysqldump --opt --where="1 limit 1000000" database
Of course, that would give you the first million rows from every table.
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Inner join vs Where
... I find it much easier to comprehend FOR INNER JOINS than the SQL-92 syntax. Your mileage may vary.
– Craig Trader
Sep 23 '08 at 17:39
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How should a model be structured in MVC? [closed]
...me, Domain Objects are completely unaware of storage - neither from where (SQL database, REST API, text file, etc.) nor even if they get saved or retrieved.
Data Mappers
These objects are only responsible for the storage. If you store information in a database, this would be where the SQL lives. Or...