mirror of https://gitee.com/bigwinds/arangodb
30 lines
1.4 KiB
Plaintext
30 lines
1.4 KiB
Plaintext
!CHAPTER HTTP Interface for Edges
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This is an introduction to ArangoDB's REST interface for edges.
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ArangoDB offers also some graph functionality. A graph consists of nodes, edges
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and properties. ArangoDB stores the information how the nodes relate to each
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other aside from the properties.
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A graph data model always consists of two collections: the relations between the
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nodes in the graphs are stored in an "edges collection", the nodes in the graph
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are stored in documents in regular collections.
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*Example*:
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- the "edge" collection stores the information that a company's reception is
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sub-unit to the services unit and the services unit is sub-unit to the
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CEO. You would express this relationship with the *to* and *_to* attributes
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- the "normal" collection stores all the properties about the reception,
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e.g. that 20 people are working there and the room number etc
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- *_from* is the [document handle](../Glossary/index.html#document_handle) of the linked vertex (incoming relation)
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- *_to* is the document handle of the linked vertex (outgoing relation)
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!SECTION Documents, Identifiers, Handles
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Edges in ArangoDB are special documents. In addition to the internal attributes
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_key, _id and _rev, they have two attributes _from and _to, which contain
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document handles, namely the start-point and the end-point of the edge.
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The values of _from and _to are immutable once saved.
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