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Expansion of variables inside single quotes in a command in Bash
...by concatenating variables. This is a bad idea similar to concatenation of SQL fragments (SQL injection!).
Usually it is possible to have placeholders in the command, and to supply the command together with variables so that the callee can receive them from the invocation arguments list.
For examp...
Which MySQL data type to use for storing boolean values
Since MySQL doesn't seem to have any 'boolean' data type, which data type do you 'abuse' for storing true/false information in MySQL?
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mongoose vs mongodb (nodejs modules/extensions), which better? and why?
...you're looking for an object modeling (ODM, a counterpart to ORMs from the SQL world) tool to skip some lower level work, you want Mongoose.
If you want a driver, because you intend to break a lot of rules that an ODM might enforce, go with MongoDB. If you want a fast driver, and can live with some...
update columns values with column of another table based on condition [duplicate]
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it's not working in mysql
– cikatomo
Sep 30 '15 at 19:30
22
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How to alter a column's data type in a PostgreSQL table?
Entering the following command into a PostgreSQL interactive terminal results in an error:
1 Answer
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Can I change a column from NOT NULL to NULL without dropping it?
... I tried with alter column and it didn't work with the latest mysql server. I tried with modify column and it worked. Strange...
– Kostas Andrianos
Aug 19 '17 at 15:29
1...
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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千万别惹程序员 - 轻松一刻 - 清泛网 - 专注C/C++及内核技术
...些精细的调优工作，明显不行。这和Ruby很像。
PHP没有MySQL，明显是被幽默了一把。不过最近对PHP的批评越来越多，不过，facebook的PHP的引擎HiPo已经很牛B了。
Perl是一本日本武士刀，是忍者玩的语言。
VB，就是一个玩具。你见...
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...