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delete_all vs destroy_all?
I am looking for the best approach to delete records from a table. For instance, I have a user whose user ID is across many tables. I want to delete this user and every record that has his ID in all tables.
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Can you give a Django app a verbose name for use throughout the admin?
...effects what's shown to the user. It's the literal string used to name the table in the database, which requires a schema migration if you're changing an existing model.
– Cerin
Apr 11 '12 at 16:14
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Code-first vs Model/Database-first [closed]
... unique index on a field or you can not delete hierarchical data in a tree table for this you need a CTE using the context.Table.SqlQuery("select..."). Model/Database first do not have these drawbacks.
– Elisabeth
Jan 31 '13 at 13:51
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count the frequency that a value occurs in a dataframe column
... x 1 columns]
See the online docs: http://pandas.pydata.org/pandas-docs/stable/groupby.html
Also value_counts() as @DSM has commented, many ways to skin a cat here
In [38]:
df['a'].value_counts()
Out[38]:
b 3
a 2
s 2
dtype: int64
If you wanted to add frequency back to the original d...
Awk学习笔记 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...置函数
控制流命令
4. awk的环境变量
Table 1. awk的环境变量
变量
描述
$n
当前记录的第n个字段，字段间由FS分隔。
$0
完整的输入记录。
ARGC
命令行参数的数目。
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Tablix: Repeat header rows on each page not working - Report Builder 3.0
I have a tablix with lots of rows that span over multiple pages. I have set the Tablix property Repeat header rows on each page but this does not work. I read somewhere that this is a known bug in Report Builder 3.0. Is this true? If not, is there something else that needs to be done?
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How to $http Synchronous call with AngularJS
...model="search"></input>
<div class="bs-example">
<table class="table" >
<thead>
<tr>
<th>#</th>
<th>Description</th>
</tr>
</thead>
<tbody>
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MongoDB and “joins” [duplicate]
...r hand will resolve relationships and return them as if they were a single table (you "join two tables into one").
You can read more about DBRef here:
http://docs.mongodb.org/manual/applications/database-references/
There are two possible solutions for resolving references. One is to do it manuall...
Case in Select Statement
...ample, the value in the SalariedFlag column of the HumanResources.Employee table is evaluated. Employees that have the SalariedFlag set to 1 are returned in order by the BusinessEntityID in descending order. Employees that have the SalariedFlag set to 0 are returned in order by the BusinessEntityID ...
【解决】Linux mysql如何重置root密码？ - 更多技术 - 清泛网 - 专注C/C++及内核技术
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4. 略过grant授权表启动mysql/MariaDB服务
启用--skip-grant-tables选项后，任何人都可以在没有密码和所有权限的情况下连接到数据库服务器：
mysqld_safe --skip-grant-tables &
上面命令末尾的＆符号将导致程序在后台运行，因此我...