69 lines
1.7 KiB
Go
69 lines
1.7 KiB
Go
package main
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import (
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"context"
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"fmt"
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"io/ioutil"
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"log"
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"os"
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"github.com/cayleygraph/cayley"
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"github.com/cayleygraph/cayley/graph"
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_ "github.com/cayleygraph/cayley/graph/kv/bolt"
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"github.com/cayleygraph/quad"
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)
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func main() {
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// File for your new BoltDB. Use path to regular file and not temporary in the real world
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tmpdir, err := ioutil.TempDir("", "example")
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if err != nil {
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log.Fatal(err)
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}
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defer os.RemoveAll(tmpdir) // clean up
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// Initialize the database
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err = graph.InitQuadStore("bolt", tmpdir, nil)
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if err != nil {
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log.Fatal(err)
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}
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// Open and use the database
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store, err := cayley.NewGraph("bolt", tmpdir, nil)
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if err != nil {
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log.Fatalln(err)
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}
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store.AddQuad(quad.Make("phrase of the day", "is of course", "Hello BoltDB!", "demo graph"))
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// Now we create the path, to get to our data
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p := cayley.StartPath(store, quad.String("phrase of the day")).Out(quad.String("is of course"))
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// This is more advanced example of the query.
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// Simpler equivalent can be found in hello_world example.
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ctx := context.TODO()
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// Now we get an iterator for the path and optimize it.
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// The second return is if it was optimized, but we don't care for now.
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its, _ := p.BuildIterator(ctx).Optimize(ctx)
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it := its.Iterate()
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// remember to cleanup after yourself
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defer it.Close()
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// While we have items
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for it.Next(ctx) {
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token := it.Result() // get a ref to a node (backend-specific)
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value, err := store.NameOf(token) // get the value in the node (RDF)
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if err != nil {
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log.Fatalln(err)
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}
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nativeValue := quad.NativeOf(value) // convert value to normal Go type
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fmt.Println(nativeValue) // print it!
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}
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if err := it.Err(); err != nil {
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log.Fatalln(err)
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}
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}
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