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Does a foreign key automatically create an index?
... I'm just about positive that PostgreSQL creates an index. I'm pretty sure MySQL does. Making the index makes a ton of sense, but IT'T NOT REQUIRED. After all, why reference something if every time the DB goes to look it up it has to do a tablescan?
– MBCook
Ma...
How to get multiple counts with one SQL query?
... entire nested query with a simple count(*) as @Mihai shows - with further MySQL only syntax simplifications.
– YoYo
Apr 1 '17 at 19:29
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App Inventor 2 SQLite 拓展：超流行兼容主流SQL语法的迷你本地数据库引擎 ...
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SQLite 拓展
SQLite
特性
如何使用
背景
属性
事件
方法
常规
事务
数据操作
绑定参数
案例
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Bash Templating: How to build configuration files from templates with Bash?
...th care, of course, since eval can execute arbitrary code. Running this as root is pretty much out of the question. Quotes in the template need to be escaped, otherwise they will be eaten by eval.
You can also use here documents if you prefer cat to echo
$ eval "cat <<< \"$(<template.t...
Vim: apply settings on files in directory
...re expanding templates (which is quite useful to fetch the current project root directory and trim it from the pathnames expanded)
– Luc Hermitte
Dec 1 '10 at 16:08
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Django, creating a custom 500/404 error page
...ing 404 errors. It finds it by looking for the variable handler404 in your root URLconf (and only in your root URLconf; setting handler404 anywhere else will have no effect), which is a string in Python dotted syntax – the same format the normal URLconf callbacks use. A 404 view itself has nothing...
How to convert array to SimpleXML
...y (
'stack' => 'overflow',
),
);
$xml = new SimpleXMLElement('<root/>');
array_walk_recursive($test_array, array ($xml, 'addChild'));
print $xml->asXML();
results in
<?xml version="1.0"?>
<root>
<blub>bla</blub>
<bar>foo</bar>
<overfl...
How to use JNDI DataSource provided by Tomcat in Spring?
...
auth="Container"
type="javax.sql.DataSource"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/TestDB"
username="pankaj"
password="pankaj123"
maxActive="100"
maxIdle="20"
minIdle="5"
maxWait="10000"/>
back to context.xml de spring add this
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What data type to use for hashed password field and what length?
...
You can actually use CHAR(length of hash) to define your datatype for MySQL because each hashing algorithm will always evaluate out to the same number of characters. For example, SHA1 always returns a 40-character hexadecimal number.
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WiX tricks and tips
...INSTALLLOCATION">
<RegistrySearch Id="RegistrySearch" Type="raw" Root="HKLM" Win64="$(var.Win64)"
Key="Software\Company\Product" Name="InstallLocation" />
</Property>
Note: WiX guru Rob Mensching has posted an excellent blog entry which goes into more detail and f...