mirror of https://gitee.com/bigwinds/arangodb
103 lines
5.2 KiB
Plaintext
103 lines
5.2 KiB
Plaintext
!CHAPTER Collection-based queries
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Normally you would want to run queries on data stored in collections. This section
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will provide several examples for that.
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!SUBSECTION Example data
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Some of the following example queries are executed on a collection *users*
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with the following initial data:
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```js
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[
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{ "id" : 100, "name" : "John", "age" : 37, "active" : true, "gender" : "m" },
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{ "id" : 101, "name" : "Fred", "age" : 36, "active" : true, "gender" : "m" },
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{ "id" : 102, "name" : "Jacob", "age" : 35, "active" : false, "gender" : "m" },
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{ "id" : 103, "name" : "Ethan", "age" : 34, "active" : false, "gender" : "m" },
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{ "id" : 104, "name" : "Michael", "age" : 33, "active" : true, "gender" : "m" },
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{ "id" : 105, "name" : "Alexander", "age" : 32, "active" : true, "gender" : "m" },
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{ "id" : 106, "name" : "Daniel", "age" : 31, "active" : true, "gender" : "m" },
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{ "id" : 107, "name" : "Anthony", "age" : 30, "active" : true, "gender" : "m" },
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{ "id" : 108, "name" : "Jim", "age" : 29, "active" : true, "gender" : "m" },
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{ "id" : 109, "name" : "Diego", "age" : 28, "active" : true, "gender" : "m" },
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{ "id" : 200, "name" : "Sophia", "age" : 37, "active" : true, "gender" : "f" },
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{ "id" : 201, "name" : "Emma", "age" : 36, "active" : true, "gender" : "f" },
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{ "id" : 202, "name" : "Olivia", "age" : 35, "active" : false, "gender" : "f" },
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{ "id" : 203, "name" : "Madison", "age" : 34, "active" : true, "gender": "f" },
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{ "id" : 204, "name" : "Chloe", "age" : 33, "active" : true, "gender" : "f" },
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{ "id" : 205, "name" : "Eva", "age" : 32, "active" : false, "gender" : "f" },
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{ "id" : 206, "name" : "Abigail", "age" : 31, "active" : true, "gender" : "f" },
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{ "id" : 207, "name" : "Isabella", "age" : 30, "active" : true, "gender" : "f" },
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{ "id" : 208, "name" : "Mary", "age" : 29, "active" : true, "gender" : "f" },
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{ "id" : 209, "name" : "Mariah", "age" : 28, "active" : true, "gender" : "f" }
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]
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```
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For some of the examples, we'll also use a collection *relations* to store
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relationships between users. The example data for *relations* are as follows:
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```js
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[
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{ "from" : 209, "to" : 205, "type" : "friend" },
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{ "from" : 206, "to" : 108, "type" : "friend" },
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{ "from" : 202, "to" : 204, "type" : "friend" },
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{ "from" : 200, "to" : 100, "type" : "friend" },
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{ "from" : 205, "to" : 101, "type" : "friend" },
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{ "from" : 209, "to" : 203, "type" : "friend" },
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{ "from" : 200, "to" : 203, "type" : "friend" },
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{ "from" : 100, "to" : 208, "type" : "friend" },
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{ "from" : 101, "to" : 209, "type" : "friend" },
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{ "from" : 206, "to" : 102, "type" : "friend" },
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{ "from" : 104, "to" : 100, "type" : "friend" },
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{ "from" : 104, "to" : 108, "type" : "friend" },
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{ "from" : 108, "to" : 209, "type" : "friend" },
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{ "from" : 206, "to" : 106, "type" : "friend" },
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{ "from" : 204, "to" : 105, "type" : "friend" },
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{ "from" : 208, "to" : 207, "type" : "friend" },
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{ "from" : 102, "to" : 108, "type" : "friend" },
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{ "from" : 207, "to" : 203, "type" : "friend" },
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{ "from" : 203, "to" : 106, "type" : "friend" },
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{ "from" : 202, "to" : 108, "type" : "friend" },
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{ "from" : 201, "to" : 203, "type" : "friend" },
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{ "from" : 105, "to" : 100, "type" : "friend" },
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{ "from" : 100, "to" : 109, "type" : "friend" },
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{ "from" : 207, "to" : 109, "type" : "friend" },
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{ "from" : 103, "to" : 203, "type" : "friend" },
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{ "from" : 208, "to" : 104, "type" : "friend" },
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{ "from" : 105, "to" : 104, "type" : "friend" },
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{ "from" : 103, "to" : 208, "type" : "friend" },
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{ "from" : 203, "to" : 107, "type" : "boyfriend" },
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{ "from" : 107, "to" : 203, "type" : "girlfriend" },
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{ "from" : 208, "to" : 109, "type" : "boyfriend" },
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{ "from" : 109, "to" : 208, "type" : "girlfriend" },
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{ "from" : 106, "to" : 205, "type" : "girlfriend" },
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{ "from" : 205, "to" : 106, "type" : "boyfriend" },
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{ "from" : 103, "to" : 209, "type" : "girlfriend" },
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{ "from" : 209, "to" : 103, "type" : "boyfriend" },
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{ "from" : 201, "to" : 102, "type" : "boyfriend" },
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{ "from" : 102, "to" : 201, "type" : "girlfriend" },
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{ "from" : 206, "to" : 100, "type" : "boyfriend" },
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{ "from" : 100, "to" : 206, "type" : "girlfriend" }
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]
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```
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!SUBSECTION Things to consider when running queries on collections
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Note that all documents created in the two collections will automatically get the
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following server-generated attributes:
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* *_id*: A unique id, consisting of [collection name](../Glossary/README.html#collection_name) and a server-side sequence value
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* *_key*: The server sequence value
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* *_rev*: The document's revision id
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Whenever you run queries on the documents in the two collections, don't be surprised if
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these additional attributes are returned as well.
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Please also note that with real-world data, you might want to create additional
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indexes on the data (left out here for brevity). Adding indexes on attributes that are
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used in *FILTER* statements may considerably speed up queries. Furthermore, instead of
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using attributes such as *id*, *from* and *to*, you might want to use the built-in
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*_id*, *_from* and *_to* attributes. Finally, [edge collection](../Glossary/README.html#edge_collection)s provide a nice way of
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establishing references / links between documents. These features have been left out here
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for brevity as well.
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