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New transaction is not allowed because there are other threads running in the session LINQ To Entity
...oblem is not specific to Entity Framework. It is related to the underlying SQL Server SqlConnection object. Evidently, in this scenario, Entity framework sees fit to start a transaction for each save. This is a terrible idea, and an argument for not using Entity Framework. My guess is that the code ...
How to create user for a db in postgresql? [closed]
I have installed PostgreSQL 8.4 on my CentOS server and connected to root user from shell and accessing the PostgreSQL shell.
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半个汉字的校验与处理(C++) - C/C++ - 清泛网 - 专注C/C++及内核技术
...串的后续处理，会带来一定的麻烦，比如在xml文档、或者SQL语句中，如果存在半个汉字，就会导致xml解析失败，或者sql执行错误的异常。为了解决这个问题，有必要找到并删除半个汉字，或者存放的时候，即便截断，也不产生新...
Oracle 分组后取每组第一条数据 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...组后取每组第一条数据Oracle 分组后取每组第一条数据的SQL如下，亲测有效：SELECT * FROM (SELECT ROW_NUMBER() OVER(PARTITION BY T field1, T Oracle 分组后取每组第一条数据的SQL如下，亲测有效：
SELECT *
FROM (SELECT ROW_NUMBER() OVER(PARTITION ...
Linq 多字段排序，二次排序 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...ordered = source.OrderByDescending( t => t.f1 ).ThenBy( t => t.f2 );类似SQL：select * from t1 order by f1 d...Linq：ordered = source.OrderByDescending( t => t.f1 ).ThenBy( t => t.f2 );
类似SQL：select * from t1 order by f1 desc ,f2 asc
这种写法里 OrderBy、ThenBy 是升序的，Ord...
Set value to NULL in MySQL
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You're probably quoting 'NULL'. NULL is a reserved word in MySQL, and can be inserted/updated without quotes:
INSERT INTO user (name, something_optional) VALUES ("Joe", NULL);
UPDATE user SET something_optional = NULL;
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How to join (merge) data frames (inner, outer, left, right)
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@MattParker I have been using sqldf package for a whole host of complex queries against dataframes, really needed it to do a self-cross join (ie data.frame cross-joining itself) I wonder how it compares from a performance perspective....???
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Fixing slow initial load for IIS
... My problem was that my app was using Windows Integrated Authentication to SQL Server and the service profile was in a different domain than the server. This caused a cross-domain authentication from IIS to SQL upon app initialization - and this was the real source of my delay. I changed to using a ...
Entity Framework code first unique column
... your model field is a string, make sure it is not set to nvarchar(MAX) in SQL Server or you will see this error with Entity Framework Code First:
Column 'x' in table 'dbo.y' is of a type that is invalid for use as a key column in an index.
The reason is because of this:
SQL Server retains...
How do I escape a reserved word in Oracle?
In TSQL I could use something like Select [table] from tablename to select a column named "table".
5 Answers
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