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App Inventor 2 开发多用户注册登录签到系统 - AppInventor连接网络微数据...
...学习成本较低。当然如果有大数据量的场景,则考虑使用MySQL进行存储,详见《App Inventor 2 如何连接MySQL数据库》。
这里主要讨论“网络微数据库”组件的用法,及如何实现我们的多用户注册、登录、签到等功能。
“网络微数...
How long is the SHA256 hash?
...+ salt, but I don't know how long to make my VARCHAR when setting up the MySQL database. What is a good length?
5 Answers...
SQLAlchemy IN clause
...is using raw SQL mode with SQLAlchemy, I use SQLAlchemy 0.9.8, python 2.7, MySQL 5.X, and MySQL-Python as connector, in this case, a tuple is needed. My code listed below:
id_list = [1, 2, 3, 4, 5] # in most case we have an integer list or set
s = text('SELECT id, content FROM myTable WHERE id IN :...
LR性能测试结果样例分析 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...务器资源监控相对来说就复杂的多了,现在常用的数据有Mysql、SQL Server、Oracle、DB2等,LoadRunner提供对后面几种数据库的监控方法,但对Mysql没有提供对应的监控方法。他不提供,咱们就自己找监控工具,我这里使用的是Spotlight,...
Count the occurrences of DISTINCT values
I am trying to find a MySQL query that will find DISTINCT values in a particular field, count the number of occurrences of that value and then order the results by the count.
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Rails 3 execute custom sql query without a model
...
How about this :
@client = TinyTds::Client.new(
:adapter => 'mysql2',
:host => 'host',
:database => 'siteconfig_development',
:username => 'username',
:password => 'password'
sql = "SELECT * FROM users"
result = @client.execute(sql)
results.each d...
How to export a Vagrant virtual machine to transfer it
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Does the "clean way" account for databases (mySQL, Wordpress) that might be inside the vm? How can that be synced over to the other pc?
– kevllar
Feb 17 '16 at 4:33
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Is storing a delimited list in a database column really that bad?
...ient table-scan. May have to resort to regular expressions, for example in MySQL:
idlist REGEXP '[[:<:]]2[[:>:]]'*
Hard to count elements in the list, or do other aggregate queries.
Hard to join the values to the lookup table they reference.
Hard to fetch the list in sorted order.
To solve th...
Subqueries vs joins
...
Here's an example of how subqueries are evaluated in MySQL 6.0.
The new optimizer will convert this kind of subqueries into joins.
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What is sharding and why is it important?
...cross multiple logical or physical nodes (in the case of my understanding (mySQL) multiple databases, most likely housed on different logical hardware). Horizontal partitioning is a less specific term, of which "Sharding" is a subset. Again using mySQL as an example, a mySQL partition is handled by...