Indexeddb:使用通配符搜索 [英] Indexeddb: search using wildcards

问题描述

我想知道是否可以使用通配符在indexeddb对象存储上执行搜索. 例如，找到所有键都以"555"开头的对象都是很方便的

I was wondering if it is possible to perform a search on an indexeddb object store using wildcards. It would be handy to find all object with a key beginning with '555' for example

推荐答案

使用复合键或键片段可以立即使用. 键在IndexedDB中的工作方式是生成一个"keyRange"对象并将其传递给光标调用.键范围传递信息，例如起始于A，结束于Z，包括两端".

This is possible out of the box using either compound keys or key fragments. The way keys work in IndexedDB is that you generate a "keyRange" object and pass it to your cursor invocation. The keyrange passes info like "start at A and end at Z, inclusive."

从本质上讲，其中内置了部分匹配；缺点是您的光标将返回键之间的所有键，您可能需要进一步过滤掉这些结果.

By nature, there is partial matching built into this; the downside is that your cursor will return any keys that come between your keys and you might have to filter down those results further.

假设您将这些单词作为对象存储库中的键:

Say you have these words as keys in a object store:

• 土豚
• 苹果
• Google
• 微软

键范围"A到Z，含"将返回所有这些，而"Ap到Z，含"将仅返回最后三个.

The key range "A to Z, inclusive" would return all of these but "Ap to Z, inclusive" would return just the last three.

我用来实现此目的的另一种技术是将过滤器"函数传递给调用IndexedDB的方法.在方法onsuccess回调内部，将结果(event.target.result)通过过滤器函数传递，如果结果返回true，则调用方法调用者的onsuccess回调.

Another technique I've used to implement this is by passing a "filter" function to my methods that invoke IndexedDB. Inside the methods onsuccess callback, pass the result (event.target.result) through your filter function and if it returns true then call your method invoker's onsuccess callback.

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