List all nodes from store

List all nodes from store #

Problem #

How can I retrieve and print all nodes from the store?

Solution #

Create Test Data: # 

package main

import (
	"github.com/cayleygraph/quad"

	// Add some predefined vocabularies
	"github.com/cayleygraph/quad/voc/rdf"
	"github.com/tombenke/cayley-cookbook-src/kbase/voc/foaf"
)

func makeQuads() []quad.Quad {
	// Generate Blank Nodes to represent the people internally
	luke := quad.RandomBlankNode()
	leia := quad.IRI("starwars:leia_organa") //quad.RandomBlankNode()

	// Create Quads about to export
	label := "people"
	quads := []quad.Quad{}
	quads = append(quads, quad.Make(luke, quad.IRI(rdf.Type), quad.IRI(foaf.Person), label))
	quads = append(quads, quad.Make(luke, quad.IRI(foaf.GivenName), "Luke", label))
	quads = append(quads, quad.Make(luke, quad.IRI(foaf.FamilyName), "Skywalker", label))
	quads = append(quads, quad.Make(luke, quad.IRI(foaf.Age), 23, label))

	quads = append(quads, quad.Make(leia, quad.IRI(rdf.Type), quad.IRI(foaf.Person), label))
	quads = append(quads, quad.Make(leia, quad.IRI(foaf.Knows), luke, label))
	quads = append(quads, quad.Make(leia, quad.IRI(foaf.GivenName), "Leia", label))
	quads = append(quads, quad.Make(leia, quad.IRI(foaf.FamilyName), "Organa", label))

	return quads
}

Retrieve and list all nodes from the store # 

package main

import (
    "fmt"
    "log"
    "reflect"
    "context"

    "github.com/cayleygraph/cayley"
)

func main() {

    // Create a brand new graph
    store, err := cayley.NewMemoryGraph()
    if err != nil {
        log.Fatalln(err)
    }

    // Create Quads about some people using Blank Nodes as references
    quads := makeQuads()

    // Add quads to the store
    for _, q := range(quads) {
        store.AddQuad(q)
    }

    printAllNodes(store)
}

func printAllNodes(store *cayley.Handle) {
    // Get the iterator that enumerates all nodes in the graph.
    it := store.NodesAllIterator()
    fmt.Printf("%v %v\n", it, reflect.TypeOf(it))
    for it.Next(context.Background()) {
        ref := it.Result()
        key := ref.Key()
        value := store.NameOf(ref)
        fmt.Printf("Ref: %v %v\n", ref, reflect.TypeOf(ref))
        fmt.Printf("Key: %v %v\n", key, reflect.TypeOf(key))
        fmt.Printf("Value: %v %v\n", value, reflect.TypeOf(value))
        fmt.Println()
    }
}

Results:

MemStoreAll *memstore.AllIterator
Ref: 1 memstore.bnode
Key: 1 memstore.bnode
Value: _:n4748188061887615063 quad.BNode

Ref: 2 memstore.bnode
Key: 2 memstore.bnode
Value: <rdf:type> quad.IRI

Ref: 3 memstore.bnode
Key: 3 memstore.bnode
Value: <foaf:Person> quad.IRI

Ref: 4 memstore.bnode
Key: 4 memstore.bnode
Value: "people" quad.String

Ref: 6 memstore.bnode
Key: 6 memstore.bnode
Value: <foaf:givenName> quad.IRI

Ref: 7 memstore.bnode
Key: 7 memstore.bnode
Value: "Luke" quad.String

Ref: 9 memstore.bnode
Key: 9 memstore.bnode
Value: <foaf:familyName> quad.IRI

Ref: 10 memstore.bnode
Key: 10 memstore.bnode
Value: "Skywalker" quad.String

Ref: 12 memstore.bnode
Key: 12 memstore.bnode
Value: <foaf:age> quad.IRI

Ref: 13 memstore.bnode
Key: 13 memstore.bnode
Value: "23"^^<xsd:integer> quad.Int

Ref: 15 memstore.bnode
Key: 15 memstore.bnode
Value: <starwars:leia_organa> quad.IRI

Ref: 17 memstore.bnode
Key: 17 memstore.bnode
Value: <foaf:knows> quad.IRI

Ref: 19 memstore.bnode
Key: 19 memstore.bnode
Value: "Leia" quad.String

Ref: 21 memstore.bnode
Key: 21 memstore.bnode
Value: "Organa" quad.String