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MySQL load NULL values from CSV data
...
MySQL manual says:
When reading data with LOAD DATA
INFILE, empty or missing columns are
updated with ''. If you want a NULL
value in a column, you should use \N
in the data file. The literal word
“NULL” ma...
Comparing two dictionaries and checking how many (key, value) pairs are equal
...t(json.dumps(diff, indent=4))
Output
{
"values_changed": {
"root['a']": {
"new_value": 2,
"old_value": 1
},
"root['nested']['b']": {
"new_value": 2,
"old_value": 1
}
}
}
Note about pretty-printing the result...
领域驱动设计系列（二）:领域Model？ - 更多技术 - 清泛网 - 专注C/C++及内核技术
...易让大家搞糊涂。 我觉得先抛开这些概念，后面再来说如何设计聚合，先简单来说。
模型
过去，我们在多层设计里定义了很多Model, 数据库的Model(DB Entity), 然后为了不依赖数据库，我们有设计了业务的Domain Model, 同时我们又设...
Error 1046 No database Selected, how to resolve?
...
You need to tell MySQL which database to use:
USE database_name;
before you create a table.
In case the database does not exist, you need to create it as:
CREATE DATABASE database_name;
followed by:
USE database_name;
...
Tree data structure in C#
...ation...
< 40 lines of code...
You just need to keep a reference to the root of the tree outside of the class,
or wrap it in another class, maybe rename to TreeNode??
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Using column alias in WHERE clause of MySQL query produces an error
...is
executed, the column value may not yet
be determined.
Copied from MySQL documentation
As pointed in the comments, using HAVING instead may do the work. Make sure to give a read at this WHERE vs HAVING though.
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常用快速产品原型设计工具推荐 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...了解用例的用户界面；
系统分析员，用来了解用户界面如何影响系统分析；
设计员，用来了解用户界面如何施加影响及它对系统“内部”的要求；
类测试人员，用来制定测试计划活动。
如何高效完成优秀原型设计，工具自...
How do I create a variable number of variables?
...s sometimes write code like this:
my_calculator.button_0 = tkinter.Button(root, text=0)
my_calculator.button_1 = tkinter.Button(root, text=1)
my_calculator.button_2 = tkinter.Button(root, text=2)
...
The coder is then left with a pile of named variables, with a coding effort of O(m * n), where m ...
What MySQL data type should be used for Latitude/Longitude with 8 decimal places?
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DECIMAL is the MySQL data-type for exact arithmetic. Unlike FLOAT its precision is fixed for any size of number, so by using it instead of FLOAT you might avoid precision errors when doing some calculations. If you were just storing and ret...
Does MySQL foreign_key_checks affect the entire database?
When I execute this command in MySQL:
6 Answers
6
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