mirror of https://gitee.com/bigwinds/arangodb
84 lines
3.6 KiB
Plaintext
84 lines
3.6 KiB
Plaintext
!CHAPTER HTTP Interface for Collections
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!SUBSECTION Collections
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This is an introduction to ArangoDB's HTTP interface for collections.
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!SUBSUBSECTION Collection
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A collection consists of documents. It is uniquely identified by its
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[collection identifier](../Glossary/index.html#collection_identifier). It also has a unique name that clients should
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use to identify and access it. Collections can be renamed. This will
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change the collection name, but not the collection identifier.
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Collections have a type that is specified by the user when the collection
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is created. There are currently two types: document and edge. The default
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type is document.
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!SUBSUBSECTION Collection Identifier
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A collection identifier lets you refer to a collection in a database.
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It is a string value and is unique within the database. Up to including
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ArangoDB 1.1, the collection identifier has been a client's primary
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means to access collections. Starting with ArangoDB 1.2, clients should
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instead use a collection's unique name to access a collection instead of
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its identifier.
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ArangoDB currently uses 64bit unsigned integer values to maintain
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collection ids internally. When returning collection ids to clients,
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ArangoDB will put them into a string to ensure the collection id is not
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clipped by clients that do not support big integers. Clients should treat
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the collection ids returned by ArangoDB as opaque strings when they store
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or use it locally.
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Note: collection ids have been returned as integers up to including ArangoDB 1.1
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!SUBSUBSECTION Collection Name
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A collection name identifies a collection in a database. It is a string
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and is unique within the database. Unlike the collection identifier it is
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supplied by the creator of the collection. The collection name must consist
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of letters, digits, and the _ (underscore) and - (dash) characters only.
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Please refer to Naming Conventions in ArangoDB for more information on valid
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collection names.
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!SUBSUBSECTION Key Generator
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ArangoDB allows using key generators for each collection. Key generators
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have the purpose of auto-generating values for the _key attribute of a document
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if none was specified by the user. By default, ArangoDB will use the traditional
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key generator. The traditional key generator will auto-generate key values that
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are strings with ever-increasing numbers. The increment values it uses are
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non-deterministic.
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Contrary, the auto increment key generator will auto-generate deterministic key
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values. Both the start value and the increment value can be defined when the
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collection is created. The default start value is 0 and the default increment
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is 1, meaning the key values it will create by default are:
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1, 2, 3, 4, 5, ...
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When creating a collection with the auto increment key generator and an increment of 5, the generated keys would be:
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1, 6, 11, 16, 21, ...
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The basic operations (create, read, update, delete) for documents are mapped
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to the standard HTTP methods (*POST*, *GET*, *PUT*, *DELETE*).
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!SECTION Address of a Collection
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All collections in ArangoDB have an unique identifier and a unique
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name. ArangoDB internally uses the collection's unique identifier to
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look up collections. This identifier however is managed by ArangoDB
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and the user has no control over it. In order to allow users use their
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own names, each collection also has a unique name, which is specified
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by the user. To access a collection from the user perspective, the
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collection name should be used, i.e.:
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http://server:port/_api/collection/collection-name
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For example: Assume that the collection identifier is *7254820* and
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the collection name is *demo*, then the URL of that collection is:
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http://localhost:8529/_api/collection/demo
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