mirror of https://gitee.com/bigwinds/arangodb
slightly improved AQL documentation
Conflicts: Documentation/UserManual/Aql.md
This commit is contained in:
Jan Steemann
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a1dc22e11b
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87284a47f9
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@ -1219,11 +1219,12 @@ AQL supports the following functions to operate on document values:
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Example usage:
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RETURN MATCHES({ "test" : 1 }, [
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{ "test" : 1, "foo" : "bar" },
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{ "foo" : 1 },
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{ "test : 1 }
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], true)
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RETURN MATCHES(
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{ "test" : 1 }, [
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{ "test" : 1, "foo" : "bar" },
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{ "foo" : 1 },
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{ "test : 1 }
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], true)
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This will return `2`, because the third example matches, and because the
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`return-index` flag is set to `true`.
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@ -1235,21 +1236,27 @@ AQL supports the following functions to operate on document values:
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For example, two documents with distinct attribute names can easily be merged into one:
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RETURN MERGE(
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{ "user1" : { "name" : "J" } },
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{ "user2" : { "name" : "T" } }
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)
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[ { "user1" : { "name" : "J" },
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"user2" : { "name" : "T" } } ]
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RETURN MERGE(
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{ "user1" : { "name" : "J" } },
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{ "user2" : { "name" : "T" } }
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)
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[
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{ "user1" : { "name" : "J" },
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"user2" : { "name" : "T" } }
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]
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When merging documents with identical attribute names, the attribute values of the
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latter documents will be used in the end result:
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return MERGE(
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{ "users" : { "name" : "J" } },
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{ "users" : { "name" : "T" } }
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)
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[ { "users" : { "name" : "T" } } ]
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RETURN MERGE(
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{ "users" : { "name" : "J" } },
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{ "users" : { "name" : "T" } }
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)
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[
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{ "users" : { "name" : "T" } }
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]
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Please note that merging will only be done for top-level attributes. If you wish to
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merge sub-attributes, you should consider using `MERGE_RECURSIVE` instead.
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@ -1261,11 +1268,14 @@ AQL supports the following functions to operate on document values:
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For example, two documents with distinct attribute names can easily be merged into one:
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RETURN MERGE_RECURSIVE(
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{ "user-1" : { "name" : "J", "livesIn" : { "city" : "LA" } } },
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{ "user-1" : { "age" : 42, "livesIn" : { "state" : "CA" } } }
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)
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[ { "user-1" : { "name" : "J", "livesIn" : { "city" : "LA", "state" : "CA" }, "age" : 42 } } ]
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RETURN MERGE_RECURSIVE(
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{ "user-1" : { "name" : "J", "livesIn" : { "city" : "LA" } } },
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{ "user-1" : { "age" : 42, "livesIn" : { "state" : "CA" } } }
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)
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[
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{ "user-1" : { "name" : "J", "livesIn" : { "city" : "LA", "state" : "CA" }, "age" : 42 } }
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]
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- @FN{HAS(@FA{document}, @FA{attributename})}: returns `true` if @FA{document} has an
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@ -1282,14 +1292,14 @@ AQL supports the following functions to operate on document values:
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Multiple attribute names can be specified by either passing multiple individual string argument
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names, or by passing a list of attribute names:
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RETURN UNSET(doc, '_id', '_key', [ 'foo', 'bar' ])
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RETURN UNSET(doc, '_id', '_key', [ 'foo', 'bar' ])
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- @FN{KEEP(@FA{document}, @FA{attributename}, ...)}: keeps only the attributes @FA{attributename}
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(can be one or many) from @FA{document}. All other attributes will be removed from the result.
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Multiple attribute names can be specified by either passing multiple individual string argument
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names, or by passing a list of attribute names:
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RETURN KEEP(doc, 'firstname', 'name', 'likes')
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RETURN KEEP(doc, 'firstname', 'name', 'likes')
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- @FN{PARSE_IDENTIFIER(@FA{document-handle})}: parses the document handle specified in
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@FA{document-handle} and returns a the handle's individual parts a separate attributes.
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@ -1298,11 +1308,17 @@ AQL supports the following functions to operate on document values:
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identifier string (e.g. `_users/1234`). Passing either a non-string or a non-document or a
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document without an `_id` attribute will result in an error.
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RETURN PARSE_IDENTIFIER('_users/my-user')
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[ { "collection" : "_users", "key" : "my-user" } ]
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RETURN PARSE_IDENTIFIER('_users/my-user')
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RETURN PARSE_IDENTIFIER({ "_id" : "mycollection/mykey", "value" : "some value" })
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[ { "collection" : "mycollection", "key" : "mykey" } ]
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[
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{ "collection" : "_users", "key" : "my-user" }
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]
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RETURN PARSE_IDENTIFIER({ "_id" : "mycollection/mykey", "value" : "some value" })
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[
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{ "collection" : "mycollection", "key" : "mykey" }
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]
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@subsubsection AqlFunctionsGeo Geo functions
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@ -1411,13 +1427,13 @@ AQL has the following functions to traverse graphs:
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- `source`: start vertex of path
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- `destination`: destination vertex of path
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Example calls:
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Example calls:
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PATHS(friends, friendrelations, "outbound", false)
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PATHS(friends, friendrelations, "outbound", false)
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FOR p IN PATHS(friends, friendrelations, "outbound")
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FILTER p.source._id == "123456/123456" && LENGTH(p.edges) == 2
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RETURN p.vertices[*].name
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FOR p IN PATHS(friends, friendrelations, "outbound")
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FILTER p.source._id == "123456/123456" && LENGTH(p.edges) == 2
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RETURN p.vertices[*].name
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- @FN{TRAVERSAL(@FA{vertexcollection}, @FA{edgecollection}, @FA{startVertex}, @FA{direction}, @FA{options})}:
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traverses the graph described by @FA{vertexcollection} and @FA{edgecollection},
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@ -1505,55 +1521,55 @@ Example calls:
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attributes `vertices` and `edges`, which are both lists. Note that `path` is only present
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in the result if the `paths` attribute is set in the @FA{options}.
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Example calls:
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Example calls:
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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strategy: "depthfirst",
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order: "postorder",
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itemOrder: "backward",
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maxDepth: 6,
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paths: true
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})
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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strategy: "depthfirst",
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order: "postorder",
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itemOrder: "backward",
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maxDepth: 6,
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paths: true
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})
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// filtering on specific edges (by specifying example edges)
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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strategy: "breadthfirst",
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order: "preorder",
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itemOrder: "forward",
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followEdges: [ { type: "knows" }, { state: "FL" } ]
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})
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// filtering on specific edges (by specifying example edges)
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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strategy: "breadthfirst",
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order: "preorder",
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itemOrder: "forward",
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followEdges: [ { type: "knows" }, { state: "FL" } ]
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})
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// filtering on specific edges and vertices
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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strategy: "breadthfirst",
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order: "preorder",
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itemOrder: "forward",
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followEdges: [ { type: "knows" }, { state: "FL" } ],
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filterVertices: [ { isActive: true }, { isDeleted: false } ],
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vertexFilterMethod: [ "prune", "exclude" ]
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})
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// filtering on specific edges and vertices
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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strategy: "breadthfirst",
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order: "preorder",
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itemOrder: "forward",
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followEdges: [ { type: "knows" }, { state: "FL" } ],
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filterVertices: [ { isActive: true }, { isDeleted: false } ],
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vertexFilterMethod: [ "prune", "exclude" ]
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})
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// using user-defined AQL functions for edge and vertex filtering
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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followEdges: "myfunctions::checkedge",
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filterVertices: "myfunctions::checkvertex"
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})
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// using user-defined AQL functions for edge and vertex filtering
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TRAVERSAL(friends, friendrelations, "friends/john", "outbound", {
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followEdges: "myfunctions::checkedge",
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filterVertices: "myfunctions::checkvertex"
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})
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// to register the custom AQL functions, execute something in the fashion of the
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// following commands in arangosh once:
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var aqlfunctions = require("org/arangodb/aql/functions");
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// to register the custom AQL functions, execute something in the fashion of the
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// following commands in arangosh once:
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var aqlfunctions = require("org/arangodb/aql/functions");
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// these are the actual filter functions
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aqlfunctions.register("myfunctions::checkedge", function (config, vertex, edge, path) {
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return (edge.type !== 'dislikes'); // don't follow these edges
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}, false);
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// these are the actual filter functions
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aqlfunctions.register("myfunctions::checkedge", function (config, vertex, edge, path) {
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return (edge.type !== 'dislikes'); // don't follow these edges
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}, false);
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aqlfunctions.register("myfunctions::checkvertex", function (config, vertex, path) {
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if (vertex.isDeleted || ! vertex.isActive) {
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return [ "prune", "exclude" ]; // exclude these and don't follow them
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}
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return [ ]; // include everything else
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}, false);
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aqlfunctions.register("myfunctions::checkvertex", function (config, vertex, path) {
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if (vertex.isDeleted || ! vertex.isActive) {
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return [ "prune", "exclude" ]; // exclude these and don't follow them
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}
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return [ ]; // include everything else
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}, false);
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- @FN{TRAVERSAL_TREE(@FA{vertexcollection}, @FA{edgecollection}, @FA{startVertex}, @FA{direction}, @FA{connectName}, @FA{options})}:
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traverses the graph described by @FA{vertexcollection} and @FA{edgecollection},
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@ -1566,11 +1582,11 @@ Example calls:
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be set up in a way that resembles a depth-first, pre-order visitation result. Thus, the
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`strategy` and `order` attributes of the @FA{options} attribute will be ignored.
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Example calls:
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Example calls:
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TRAVERSAL_TREE(friends, friendrelations, "friends/john", "outbound", "likes", {
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itemOrder: "forward"
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})
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TRAVERSAL_TREE(friends, friendrelations, "friends/john", "outbound", "likes", {
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itemOrder: "forward"
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})
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When using one of AQL's graph functions please make sure that the graph does not contain cycles,
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or that you at least specify some maximum depth or uniqueness criteria for a traversal.
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@ -1647,37 +1663,37 @@ time and memory for the result set.
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attributes `vertices` and `edges`, which are both lists. Note that `path` is only present
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in the result if the `paths` attribute is set in the @FA{options}.
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Example calls:
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Example calls:
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SHORTEST_PATH(cities, motorways, "cities/CGN", "cities/MUC", "outbound", {
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paths: true
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})
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SHORTEST_PATH(cities, motorways, "cities/CGN", "cities/MUC", "outbound", {
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paths: true
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})
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// using a user-defined distance function
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SHORTEST_PATH(cities, motorways, "cities/CGN", "cities/MUC", "outbound", {
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paths: true,
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distance: "myfunctions::citydistance"
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})
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// using a user-defined distance function
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SHORTEST_PATH(cities, motorways, "cities/CGN", "cities/MUC", "outbound", {
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paths: true,
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distance: "myfunctions::citydistance"
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})
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// using a user-defined function to filter edges
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SHORTEST_PATH(cities, motorways, "cities/CGN", "cities/MUC", "outbound", {
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paths: true,
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followEdges: "myfunctions::checkedge"
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})
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// using a user-defined function to filter edges
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SHORTEST_PATH(cities, motorways, "cities/CGN", "cities/MUC", "outbound", {
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paths: true,
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followEdges: "myfunctions::checkedge"
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})
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// to register a custom AQL distance function, execute something in the fashion of the
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// following commands in arangosh once:
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var aqlfunctions = require("org/arangodb/aql/functions");
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// to register a custom AQL distance function, execute something in the fashion of the
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// following commands in arangosh once:
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var aqlfunctions = require("org/arangodb/aql/functions");
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// this is the actual distance function
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aqlfunctions.register("myfunctions::distance", function (config, vertex1, vertex2, edge) {
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return Math.sqrt(Math.pow(vertex1.x - vertex2.x) + Math.pow(vertex1.y - vertex2.y));
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}, false);
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// this is the actual distance function
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aqlfunctions.register("myfunctions::distance", function (config, vertex1, vertex2, edge) {
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return Math.sqrt(Math.pow(vertex1.x - vertex2.x) + Math.pow(vertex1.y - vertex2.y));
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}, false);
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// this is the filter function for the edges
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aqlfunctions.register("myfunctions::checkedge", function (config, vertex, edge, path) {
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return (edge.underConstruction === false); // don't follow these edges
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}, false);
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// this is the filter function for the edges
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aqlfunctions.register("myfunctions::checkedge", function (config, vertex, edge, path) {
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return (edge.underConstruction === false); // don't follow these edges
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}, false);
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- @FN{EDGES(@FA{edgecollection}, @FA{startvertex}, @FA{direction}, @FA{edgeexamples})}:
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return all edges connected to the vertex @FA{startvertex} as a list. The possible values for
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@ -1691,10 +1707,10 @@ Example calls:
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To not restrict the result to specific connections, @FA{edgeexamples} should be left
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unspecified.
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Example calls:
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Example calls:
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EDGES(friendrelations, "friends/john", "outbound")
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EDGES(friendrelations, "friends/john", "any", [ { "$label": "knows" } ])
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EDGES(friendrelations, "friends/john", "outbound")
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EDGES(friendrelations, "friends/john", "any", [ { "$label": "knows" } ])
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- @FN{NEIGHBORS(@FA{vertexcollection}, @FA{edgecollection}, @FA{startvertex}, @FA{direction}, @FA{edgeexamples})}:
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return all neighbors that are directly connected to the vertex @FA{startvertex} as a list.
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@ -1708,10 +1724,10 @@ Example calls:
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To not restrict the result to specific connections, @FA{edgeexamples} should be left
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unspecified.
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Example calls:
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Example calls:
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NEIGHBORS(friends, friendrelations, "friends/john", "outbound")
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NEIGHBORS(users, usersrelations, "users/john", "any", [ { "$label": "recommends" } ] )
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NEIGHBORS(friends, friendrelations, "friends/john", "outbound")
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NEIGHBORS(users, usersrelations, "users/john", "any", [ { "$label": "recommends" } ] )
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@subsubsection AqlFunctionsControl Control flow functions
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@ -16,6 +16,17 @@ TOC {#AqlTOC}
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- @ref AqlData
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- @ref AqlOperators
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- @ref AqlFunctions
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- @ref AqlFunctionsCasting
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- @ref AqlFunctionsChecking
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- @ref AqlFunctionsString
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- @ref AqlFunctionsNumeric
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- @ref AqlFunctionsList
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- @ref AqlFunctionsDocument
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- @ref AqlFunctionsGeo
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- @ref AqlFunctionsFulltext
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- @ref AqlFunctionsGraph
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- @ref AqlFunctionsControl
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- @ref AqlFunctionsMisc
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- @ref AqlOperations
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- @ref AqlOperationFor
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- @ref AqlOperationReturn
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