什么是“文档数据存储”和“键值数据存储”？ [英] What is 'document data store' and 'key-value data store'?
问题描述
什么是文档数据存储？什么是键值数据存储？
What is document data store? What is key-value data store?
请用非常简单的一般词语描述每个键值对的机制。 p>
Please, describe in very simple and general words the mechanisms which stand behind each of them.
推荐答案
在文档数据存储中，每个记录都有多个字段，类似于关系数据库。
In a document data store each record has multiple fields, similar to a relational database. It also has secondary indexes.
示例记录：
"id" => 12345,
"name" => "Fred",
"age" => 20,
"email" => "fred@example.com"
然后您可以按ID，姓名，年龄或电子邮件进行查询。
Then you could query by id, name, age, or email.
键/值存储更像是一个大的哈希表，而不是传统的数据库：每个键对应一个值，看起来一个键是唯一的方式访问记录。
A key/value store is more like a big hash table than a traditional database: each key corresponds with a value and looking things up by that one key is the only way to access a record. This means it's much simpler and often faster, but it's difficult to use for complex data.
示例记录：
12345 => "Fred,fred@example.com,20"
您的查询条件只能使用12345。您无法查询姓名，电子邮件或年龄。
You can only use 12345 for your query criteria. You can't query for name, email, or age.
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