示例#1
0
文件: db.go 项目: RamboWANG/cayley
func Init(cfg *config.Config) error {
	if !graph.IsPersistent(cfg.DatabaseType) {
		return fmt.Errorf("ignoring unproductive database initialization request: %v", ErrNotPersistent)
	}

	return graph.InitQuadStore(cfg.DatabaseType, cfg.DatabasePath, cfg.DatabaseOptions)
}
示例#2
0
func loadGraph(path string) (*cayley.Handle, error) {
	*graph.IgnoreDup = true

	err := graph.InitQuadStore("leveldb", path, map[string]interface{}{
		"ignore_duplicate": true,
	})
	if err == graph.ErrDatabaseExists {
		log.Print(err)
	} else if err != nil {
		return nil, err
	}
	return cayley.NewGraph("leveldb", path, nil)
}
示例#3
0
文件: main.go 项目: rlugojr/cayley
func main() {
	// File for your new BoltDB. Use path to regular file and not temporary in the real world
	tmpfile, err := ioutil.TempFile("", "example")
	if err != nil {
		log.Fatal(err)
	}

	defer os.Remove(tmpfile.Name()) // clean up

	// Initialize the database
	graph.InitQuadStore("bolt", tmpfile.Name(), nil)

	// Open and use the database
	store, err := cayley.NewGraph("bolt", tmpfile.Name(), nil)
	if err != nil {
		log.Fatalln(err)
	}

	store.AddQuad(quad.Make("phrase of the day", "is of course", "Hello BoltDB!", "demo graph"))

	// Now we create the path, to get to our data
	p := cayley.StartPath(store, quad.String("phrase of the day")).Out(quad.String("is of course"))

	// This is more advanced example of the query.
	// Simpler equivalent can be found in hello_world example.

	// Now we get an iterator for the path and optimize it.
	// The second return is if it was optimized, but we don't care for now.
	it, _ := p.BuildIterator().Optimize()

	// Optimize iterator on quad store level.
	// After this step iterators will be replaced with backend-specific ones.
	it, _ = store.OptimizeIterator(it)

	// remember to cleanup after yourself
	defer it.Close()

	// While we have items
	for it.Next() {
		token := it.Result()                // get a ref to a node (backend-specific)
		value := store.NameOf(token)        // get the value in the node (RDF)
		nativeValue := quad.NativeOf(value) // convert value to normal Go type

		fmt.Println(nativeValue) // print it!
	}
	if err := it.Err(); err != nil {
		log.Fatalln(err)
	}
}
示例#4
0
// InitQuadStore initializes the quadstore.
func InitQuadStore(mongoURL string) error {
	cfg, err := url.Parse(mongoURL)
	if err != nil {
		return err
	}

	// Form the Cayley connection options.
	opts := parseMongoURL(cfg)

	if err := graph.InitQuadStore("mongo", cfg.Host, opts); err != nil {
		return err
	}

	return nil
}