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MongoDB or CouchDB - fit for production? [closed]
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We are running CouchDB as a replacemant for MySQL for our shops (70.0000 items/shop, a total of 4 million attributes of all items, cross connections between items).
Our goals were:
Easy replication from a master-db to several clients with different documents.
Fast p...
How to get ER model of database from server with Workbench
...y to get an ER model of a database from the server that is connected to my MySQL Workbench?
4 Answers
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MySQL, better to insert NULL or empty string?
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Better to Insert NULL for consistency in your database in MySQL. Foreign keys can be stored as NULL but NOT as empty strings.
You will have issues with an empty string in the constraints.
You may have to insert a fake record with a unique empty string to satisfy a Foreign Key cons...
Copy file or directories recursively in Python
...of copying files and folders recursively. (Python 3.X)
import os, shutil
root_src_dir = r'C:\MyMusic' #Path/Location of the source directory
root_dst_dir = 'D:MusicBackUp' #Path to the destination folder
for src_dir, dirs, files in os.walk(root_src_dir):
dst_dir = src_dir.replace(root_src...
boost多索引容器multi_index_container实战 - C/C++ - 清泛网 - 专注C/C++及内核技术
...些知识有过了解
什么是多索引容器？为什么要使用它？如何使用？
接下来一一回答以上的问题。
想必大家在实际开发中一定多多少少会遇到以下的问题，我需要创建一个map，并且需要两种方式去索引，比如：创建一个<学号,...
Explain Morris inorder tree traversal without using stacks or recursion
...works:
X
/ \
Y Z
/ \ / \
A B C D
First, X is the root, so it is initialized as current. X has a left child, so X is made the rightmost right child of X's left subtree -- the immediate predecessor to X in an inorder traversal. So X is made the right child of B, then current ...
How to change the docker image installation directory?
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With recent versions of Docker, you would set the value of the data-root parameter to your custom path, in /etc/docker/daemon.json
(according to https://docs.docker.com/engine/reference/commandline/dockerd/#daemon-configuration-file).
With older versions, you can change Docker's storage base...
MySQL join with where clause
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Unknown Column In Where Clause
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See the following MySQL manual page: http://dev.mysql.com/doc/refman/5.0/en/select.html
"A select_expr can be given an alias
using AS alias_name. The alias is used
as the expression's column name and
can be used in GROUP BY, ORDER BY...
How to create a multi-tenant database with shared table structures?
Our software currently runs on MySQL. The data of all tenants is stored in the same schema. Since we are using Ruby on Rails we can easily determine which data belongs to which tenant. However there are some companies of course who fear that their data might be compromised, so we are evaluating othe...