Collation Locales and Default Parameters
排序规则允许用户为字符串比较指定特定于语言的规则,例如字母大小写和重音符号规则。
行为
某些排序规则语言环境会有一些变体,这些变体采用特定于语言的特殊规则。若要指定语言环境变体,请使用以下语法:
{ "locale" : "<locale code>@collation=<variant>" }
例如,若要使用中文排序规则的 unihan
变体:
{ "locale" : "zh@collation=unihan" }
See the collation page for a full description of collation behavior and syntax.
Supported Languages and Locales
MongoDB's collation feature supports the following languages. The following table lists the supported languages and the associated locales as defined by ICU Locale ID. [1]
|
|
提示
To explicitly specify simple binary comparison, specify locale
value of "simple"
.
[1] | To request support for a locale, please file a JIRA ticket with the Server project |
Collation Default Parameters
A collation document contains several
optional parameters in
addition to the required locale
parameter. Depending on which
locale
you use, the default parameters may be different.
See the collation page for a
full description of collation syntax.
The following default parameters are consistent across all locales:
caseLevel : false
strength : 3
numericOrdering : false
maxVariable : punct
The following table shows the default collation parameters which may vary across different locales:
Locale | caseFirst | alternate | normalization | backwards |
---|---|---|---|---|
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