mirror of https://gitee.com/bigwinds/arangodb
40 lines
2.4 KiB
Markdown
40 lines
2.4 KiB
Markdown
Databases, Collections and Documents
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Databases are sets of collections. Collections store records, which are referred
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to as documents. Collections are the equivalent of tables in RDBMS, and
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documents can be thought of as rows in a table. The difference is that you don't
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define what columns (or rather attributes) there will be in advance. Every
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document in any collection can have arbitrary attribute keys and
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values. Documents in a single collection will likely have a similar structure in
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practice however, but the database system itself does not impose it and will
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operate stable and fast no matter how your data looks like.
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Read more in the [data-model concepts](../DataModeling/Concepts.md) chapter.
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For now, you can stick with the default `_system` database and use the web
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interface to create collections and documents. Start by clicking the
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*COLLECTIONS* menu entry, then the *Add Collection* tile. Give it a name, e.g.
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*users*, leave the other settings unchanged (we want it to be a document
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collection) and *Save* it. A new tile labeled *users* should show up, which
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you can click to open.
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There will be *No documents* yet. Click the green circle with the white plus
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on the right-hand side to create a first document in this collection. A dialog
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will ask you for a `_key`. You can leave the field blank and click *Create* to
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let the database system assign an automatically generated (unique) key. Note
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that the `_key` property is immutable, which means you can not change it once
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the document is created. What you can use as document key is described in the
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[naming conventions](../DataModeling/NamingConventions/DocumentKeys.md).
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An automatically generated key could be `"9883"` (`_key` is always a string!),
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and the document `_id` would be `"users/9883"` in that case. Aside from a few
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system attributes, there is nothing in this document yet. Let's add a custom
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attribute by clicking the icon to the left of *(empty object)*, then *Append*.
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Two input fields will become available, *FIELD* (attribute key) and *VALUE*
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(attribute value). Type `name` as key and your name as value. *Append* another
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attribute, name it `age` and set it to your age. Click *Save* to persist the
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changes. If you click on *Collection: users* at the top on the right-hand side
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of the ArangoDB logo, the document browser will show the documents in the
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*users* collection and you will see the document you just created in the list.
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