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LINQ: When to use SingleOrDefault vs. FirstOrDefault() with filtering criteria
... @memetolsen Consider the code spit for the two with LINQ to SQL - FirstOrDefault uses Top 1. SingleOrDefault uses Top 2.
– Jim Wooley
Jun 14 '13 at 14:29
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Memcached下一站：HandlerSocket！ - 更多技术 - 清泛网 - 专注C/C++及内核技术
Memcached下一站：HandlerSocket！目前使用MySQL的网站，多半同时使用Memcached作为键值缓存。虽然这样的架构极其流行，有众多的案例，但过于依赖Memcached，无形中让Memcach...目前使用MySQL的网站，多半同时使用Memcached作为键值缓存。虽...
Unpivot with column name
... s
unpivot
(
marks
for subject in (Maths, Science, English)
) u;
See SQL Fiddle with demo
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IN vs OR in the SQL WHERE Clause
...hen dealing with big databases, which performs better, IN or OR in the SQL Where -clause?
6 Answers
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What's the difference between NOT EXISTS vs. NOT IN vs. LEFT JOIN WHERE IS NULL?
It seems to me that you can do the same thing in a SQL query using either NOT EXISTS, NOT IN, or LEFT JOIN WHERE IS NULL. For example:
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How long should SQL email fields be? [duplicate]
...I don't see nvarchar anywhere... do I need to set that up manually with an SQL statement, or am I just missing it somewhere?
– Mala
Aug 19 '09 at 1:50
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Check if SQL Connection is Open or Closed
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You should be using SqlConnection.State
e.g,
using System.Data;
if (myConnection != null && myConnection.State == ConnectionState.Closed)
{
// do something
// ...
}
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SQL, Postgres OIDs, What are they and why are they useful?
I am looking at some PostgreSQL table creation and I stumbled upon this:
4 Answers
4
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Entity Framework 4 vs NHibernate [closed]
...apping, better integration with stored procs / database functions / custom SQL / triggers, support for formula properties and so on. IMO it's basically just more mature as an ORM.
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sqlalchemy IS NOT NULL select
How can I add the filter as in SQL to select values that are NOT NULL from a certain column ?
3 Answers
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