大约有 3,559 项符合查询结果（耗时：0.0129秒） [XML]
Entity Framework 4 Single() vs First() vs FirstOrDefault()
...
Another point is when querying a sql database, Single or SingleOrDefault will query for 2 records (limit 2) while First or FirstOrDefault will query for 1 (limit 1).
– Bart Calixto
Mar 14 '15 at 4:08
...
postgresql - replace all instances of a string within text field
In postgresql, how do I replace all instances of a string within a database column?
4 Answers
...
Count with IF condition in MySQL query
...
Or even SUM(ccc_news_comments.id = 'approved') as a MySQL-specific trick
– mojuba
Jan 21 '13 at 20:44
1
...
Is Mono ready for prime time? [closed]
...ort, as those have little to no dependencies on Win32 and you can even use SQL server or other popular databases (there are plenty of bundled database providers with Mono).
Windows.Forms porting is sometimes trickier because developers like to escape the .NET sandbox and P/Invoke their brains ou...
How to get a one-dimensional scalar array as a doctrine dql query result?
...array of values from the id column of the Auction table.
If this was a raw SQL I would write:
5 Answers
...
postgresql: INSERT INTO … (SELECT * …)
I'm not sure if its standard SQL:
6 Answers
6
...
Select DISTINCT individual columns in django?
...
It's quite simple actually if you're using PostgreSQL, just use distinct(columns) (documentation).
Productorder.objects.all().distinct('category')
Note that this feature has been included in Django since 1.4
...
Default string initialization: NULL or Empty? [closed]
...is no way to accurately represent, say, a varchar( 100 ) NOT NULL field in SQL Server using a C# type.
Other languages, such as Spec #, do allow this.
In my opinion, C#'s inability to define a string that doesn't allow null is just as bad as its previous inability to define an int that does allow ...
Error: Tablespace for table xxx exists. Please DISCARD the tablespace before IMPORT
I am fairly new to MySQL and I am getting a pretty interesting error on which I cannot find any help via google and the stackoverflow search.
...
What does java:comp/env/ do?
... lookup using "java:comp/env/foo". Have a look at blog.cherouvim.com/javax-sql-datasource-exposed-through-jndi
– cherouvim
Nov 5 '10 at 7:57
...