Move code to src/ and tests/

1 files changed, 817 insertions, 0 deletions

diff --git a/tests/cursor_test.go b/tests/cursor_test.go
new file mode 100644
index 0000000..562d60f
--- /dev/null
+++ b/tests/cursor_test.go
@@ -0,0 +1,817 @@
+package bolt_test
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"log"
+	"os"
+	"reflect"
+	"sort"
+	"testing"
+	"testing/quick"
+
+	"github.com/boltdb/bolt"
+)
+
+// Ensure that a cursor can return a reference to the bucket that created it.
+func TestCursor_Bucket(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if cb := b.Cursor().Bucket(); !reflect.DeepEqual(cb, b) {
+			t.Fatal("cursor bucket mismatch")
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx cursor can seek to the appropriate keys.
+func TestCursor_Seek(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("foo"), []byte("0001")); err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("bar"), []byte("0002")); err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("baz"), []byte("0003")); err != nil {
+			t.Fatal(err)
+		}
+
+		if _, err := b.CreateBucket([]byte("bkt")); err != nil {
+			t.Fatal(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.View(func(tx *bolt.Tx) error {
+		c := tx.Bucket([]byte("widgets")).Cursor()
+
+		// Exact match should go to the key.
+		if k, v := c.Seek([]byte("bar")); !bytes.Equal(k, []byte("bar")) {
+			t.Fatalf("unexpected key: %v", k)
+		} else if !bytes.Equal(v, []byte("0002")) {
+			t.Fatalf("unexpected value: %v", v)
+		}
+
+		// Inexact match should go to the next key.
+		if k, v := c.Seek([]byte("bas")); !bytes.Equal(k, []byte("baz")) {
+			t.Fatalf("unexpected key: %v", k)
+		} else if !bytes.Equal(v, []byte("0003")) {
+			t.Fatalf("unexpected value: %v", v)
+		}
+
+		// Low key should go to the first key.
+		if k, v := c.Seek([]byte("")); !bytes.Equal(k, []byte("bar")) {
+			t.Fatalf("unexpected key: %v", k)
+		} else if !bytes.Equal(v, []byte("0002")) {
+			t.Fatalf("unexpected value: %v", v)
+		}
+
+		// High key should return no key.
+		if k, v := c.Seek([]byte("zzz")); k != nil {
+			t.Fatalf("expected nil key: %v", k)
+		} else if v != nil {
+			t.Fatalf("expected nil value: %v", v)
+		}
+
+		// Buckets should return their key but no value.
+		if k, v := c.Seek([]byte("bkt")); !bytes.Equal(k, []byte("bkt")) {
+			t.Fatalf("unexpected key: %v", k)
+		} else if v != nil {
+			t.Fatalf("expected nil value: %v", v)
+		}
+
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestCursor_Delete(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	const count = 1000
+
+	// Insert every other key between 0 and $count.
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		for i := 0; i < count; i += 1 {
+			k := make([]byte, 8)
+			binary.BigEndian.PutUint64(k, uint64(i))
+			if err := b.Put(k, make([]byte, 100)); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if _, err := b.CreateBucket([]byte("sub")); err != nil {
+			t.Fatal(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		bound := make([]byte, 8)
+		binary.BigEndian.PutUint64(bound, uint64(count/2))
+		for key, _ := c.First(); bytes.Compare(key, bound) < 0; key, _ = c.Next() {
+			if err := c.Delete(); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		c.Seek([]byte("sub"))
+		if err := c.Delete(); err != bolt.ErrIncompatibleValue {
+			t.Fatalf("unexpected error: %s", err)
+		}
+
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.View(func(tx *bolt.Tx) error {
+		stats := tx.Bucket([]byte("widgets")).Stats()
+		if stats.KeyN != count/2+1 {
+			t.Fatalf("unexpected KeyN: %d", stats.KeyN)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx cursor can seek to the appropriate keys when there are a
+// large number of keys. This test also checks that seek will always move
+// forward to the next key.
+//
+// Related: https://github.com/boltdb/bolt/pull/187
+func TestCursor_Seek_Large(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	var count = 10000
+
+	// Insert every other key between 0 and $count.
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		for i := 0; i < count; i += 100 {
+			for j := i; j < i+100; j += 2 {
+				k := make([]byte, 8)
+				binary.BigEndian.PutUint64(k, uint64(j))
+				if err := b.Put(k, make([]byte, 100)); err != nil {
+					t.Fatal(err)
+				}
+			}
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.View(func(tx *bolt.Tx) error {
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		for i := 0; i < count; i++ {
+			seek := make([]byte, 8)
+			binary.BigEndian.PutUint64(seek, uint64(i))
+
+			k, _ := c.Seek(seek)
+
+			// The last seek is beyond the end of the the range so
+			// it should return nil.
+			if i == count-1 {
+				if k != nil {
+					t.Fatal("expected nil key")
+				}
+				continue
+			}
+
+			// Otherwise we should seek to the exact key or the next key.
+			num := binary.BigEndian.Uint64(k)
+			if i%2 == 0 {
+				if num != uint64(i) {
+					t.Fatalf("unexpected num: %d", num)
+				}
+			} else {
+				if num != uint64(i+1) {
+					t.Fatalf("unexpected num: %d", num)
+				}
+			}
+		}
+
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a cursor can iterate over an empty bucket without error.
+func TestCursor_EmptyBucket(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+	if err := db.Update(func(tx *bolt.Tx) error {
+		_, err := tx.CreateBucket([]byte("widgets"))
+		return err
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.View(func(tx *bolt.Tx) error {
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		k, v := c.First()
+		if k != nil {
+			t.Fatalf("unexpected key: %v", k)
+		} else if v != nil {
+			t.Fatalf("unexpected value: %v", v)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx cursor can reverse iterate over an empty bucket without error.
+func TestCursor_EmptyBucketReverse(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		_, err := tx.CreateBucket([]byte("widgets"))
+		return err
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.View(func(tx *bolt.Tx) error {
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		k, v := c.Last()
+		if k != nil {
+			t.Fatalf("unexpected key: %v", k)
+		} else if v != nil {
+			t.Fatalf("unexpected value: %v", v)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx cursor can iterate over a single root with a couple elements.
+func TestCursor_Iterate_Leaf(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("baz"), []byte{}); err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("foo"), []byte{0}); err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("bar"), []byte{1}); err != nil {
+			t.Fatal(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+	tx, err := db.Begin(false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	c := tx.Bucket([]byte("widgets")).Cursor()
+
+	k, v := c.First()
+	if !bytes.Equal(k, []byte("bar")) {
+		t.Fatalf("unexpected key: %v", k)
+	} else if !bytes.Equal(v, []byte{1}) {
+		t.Fatalf("unexpected value: %v", v)
+	}
+
+	k, v = c.Next()
+	if !bytes.Equal(k, []byte("baz")) {
+		t.Fatalf("unexpected key: %v", k)
+	} else if !bytes.Equal(v, []byte{}) {
+		t.Fatalf("unexpected value: %v", v)
+	}
+
+	k, v = c.Next()
+	if !bytes.Equal(k, []byte("foo")) {
+		t.Fatalf("unexpected key: %v", k)
+	} else if !bytes.Equal(v, []byte{0}) {
+		t.Fatalf("unexpected value: %v", v)
+	}
+
+	k, v = c.Next()
+	if k != nil {
+		t.Fatalf("expected nil key: %v", k)
+	} else if v != nil {
+		t.Fatalf("expected nil value: %v", v)
+	}
+
+	k, v = c.Next()
+	if k != nil {
+		t.Fatalf("expected nil key: %v", k)
+	} else if v != nil {
+		t.Fatalf("expected nil value: %v", v)
+	}
+
+	if err := tx.Rollback(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx cursor can iterate in reverse over a single root with a couple elements.
+func TestCursor_LeafRootReverse(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("baz"), []byte{}); err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("foo"), []byte{0}); err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("bar"), []byte{1}); err != nil {
+			t.Fatal(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+	tx, err := db.Begin(false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c := tx.Bucket([]byte("widgets")).Cursor()
+
+	if k, v := c.Last(); !bytes.Equal(k, []byte("foo")) {
+		t.Fatalf("unexpected key: %v", k)
+	} else if !bytes.Equal(v, []byte{0}) {
+		t.Fatalf("unexpected value: %v", v)
+	}
+
+	if k, v := c.Prev(); !bytes.Equal(k, []byte("baz")) {
+		t.Fatalf("unexpected key: %v", k)
+	} else if !bytes.Equal(v, []byte{}) {
+		t.Fatalf("unexpected value: %v", v)
+	}
+
+	if k, v := c.Prev(); !bytes.Equal(k, []byte("bar")) {
+		t.Fatalf("unexpected key: %v", k)
+	} else if !bytes.Equal(v, []byte{1}) {
+		t.Fatalf("unexpected value: %v", v)
+	}
+
+	if k, v := c.Prev(); k != nil {
+		t.Fatalf("expected nil key: %v", k)
+	} else if v != nil {
+		t.Fatalf("expected nil value: %v", v)
+	}
+
+	if k, v := c.Prev(); k != nil {
+		t.Fatalf("expected nil key: %v", k)
+	} else if v != nil {
+		t.Fatalf("expected nil value: %v", v)
+	}
+
+	if err := tx.Rollback(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx cursor can restart from the beginning.
+func TestCursor_Restart(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("bar"), []byte{}); err != nil {
+			t.Fatal(err)
+		}
+		if err := b.Put([]byte("foo"), []byte{}); err != nil {
+			t.Fatal(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	tx, err := db.Begin(false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	c := tx.Bucket([]byte("widgets")).Cursor()
+
+	if k, _ := c.First(); !bytes.Equal(k, []byte("bar")) {
+		t.Fatalf("unexpected key: %v", k)
+	}
+	if k, _ := c.Next(); !bytes.Equal(k, []byte("foo")) {
+		t.Fatalf("unexpected key: %v", k)
+	}
+
+	if k, _ := c.First(); !bytes.Equal(k, []byte("bar")) {
+		t.Fatalf("unexpected key: %v", k)
+	}
+	if k, _ := c.Next(); !bytes.Equal(k, []byte("foo")) {
+		t.Fatalf("unexpected key: %v", k)
+	}
+
+	if err := tx.Rollback(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a cursor can skip over empty pages that have been deleted.
+func TestCursor_First_EmptyPages(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	// Create 1000 keys in the "widgets" bucket.
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		for i := 0; i < 1000; i++ {
+			if err := b.Put(u64tob(uint64(i)), []byte{}); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	// Delete half the keys and then try to iterate.
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte("widgets"))
+		for i := 0; i < 600; i++ {
+			if err := b.Delete(u64tob(uint64(i))); err != nil {
+				t.Fatal(err)
+			}
+		}
+
+		c := b.Cursor()
+		var n int
+		for k, _ := c.First(); k != nil; k, _ = c.Next() {
+			n++
+		}
+		if n != 400 {
+			t.Fatalf("unexpected key count: %d", n)
+		}
+
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx can iterate over all elements in a bucket.
+func TestCursor_QuickCheck(t *testing.T) {
+	f := func(items testdata) bool {
+		db := MustOpenDB()
+		defer db.MustClose()
+
+		// Bulk insert all values.
+		tx, err := db.Begin(true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, item := range items {
+			if err := b.Put(item.Key, item.Value); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if err := tx.Commit(); err != nil {
+			t.Fatal(err)
+		}
+
+		// Sort test data.
+		sort.Sort(items)
+
+		// Iterate over all items and check consistency.
+		var index = 0
+		tx, err = db.Begin(false)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		for k, v := c.First(); k != nil && index < len(items); k, v = c.Next() {
+			if !bytes.Equal(k, items[index].Key) {
+				t.Fatalf("unexpected key: %v", k)
+			} else if !bytes.Equal(v, items[index].Value) {
+				t.Fatalf("unexpected value: %v", v)
+			}
+			index++
+		}
+		if len(items) != index {
+			t.Fatalf("unexpected item count: %v, expected %v", len(items), index)
+		}
+
+		if err := tx.Rollback(); err != nil {
+			t.Fatal(err)
+		}
+
+		return true
+	}
+	if err := quick.Check(f, qconfig()); err != nil {
+		t.Error(err)
+	}
+}
+
+// Ensure that a transaction can iterate over all elements in a bucket in reverse.
+func TestCursor_QuickCheck_Reverse(t *testing.T) {
+	f := func(items testdata) bool {
+		db := MustOpenDB()
+		defer db.MustClose()
+
+		// Bulk insert all values.
+		tx, err := db.Begin(true)
+		if err != nil {
+			t.Fatal(err)
+		}
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		for _, item := range items {
+			if err := b.Put(item.Key, item.Value); err != nil {
+				t.Fatal(err)
+			}
+		}
+		if err := tx.Commit(); err != nil {
+			t.Fatal(err)
+		}
+
+		// Sort test data.
+		sort.Sort(revtestdata(items))
+
+		// Iterate over all items and check consistency.
+		var index = 0
+		tx, err = db.Begin(false)
+		if err != nil {
+			t.Fatal(err)
+		}
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		for k, v := c.Last(); k != nil && index < len(items); k, v = c.Prev() {
+			if !bytes.Equal(k, items[index].Key) {
+				t.Fatalf("unexpected key: %v", k)
+			} else if !bytes.Equal(v, items[index].Value) {
+				t.Fatalf("unexpected value: %v", v)
+			}
+			index++
+		}
+		if len(items) != index {
+			t.Fatalf("unexpected item count: %v, expected %v", len(items), index)
+		}
+
+		if err := tx.Rollback(); err != nil {
+			t.Fatal(err)
+		}
+
+		return true
+	}
+	if err := quick.Check(f, qconfig()); err != nil {
+		t.Error(err)
+	}
+}
+
+// Ensure that a Tx cursor can iterate over subbuckets.
+func TestCursor_QuickCheck_BucketsOnly(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if _, err := b.CreateBucket([]byte("foo")); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := b.CreateBucket([]byte("bar")); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := b.CreateBucket([]byte("baz")); err != nil {
+			t.Fatal(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.View(func(tx *bolt.Tx) error {
+		var names []string
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		for k, v := c.First(); k != nil; k, v = c.Next() {
+			names = append(names, string(k))
+			if v != nil {
+				t.Fatalf("unexpected value: %v", v)
+			}
+		}
+		if !reflect.DeepEqual(names, []string{"bar", "baz", "foo"}) {
+			t.Fatalf("unexpected names: %+v", names)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// Ensure that a Tx cursor can reverse iterate over subbuckets.
+func TestCursor_QuickCheck_BucketsOnly_Reverse(t *testing.T) {
+	db := MustOpenDB()
+	defer db.MustClose()
+
+	if err := db.Update(func(tx *bolt.Tx) error {
+		b, err := tx.CreateBucket([]byte("widgets"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		if _, err := b.CreateBucket([]byte("foo")); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := b.CreateBucket([]byte("bar")); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := b.CreateBucket([]byte("baz")); err != nil {
+			t.Fatal(err)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := db.View(func(tx *bolt.Tx) error {
+		var names []string
+		c := tx.Bucket([]byte("widgets")).Cursor()
+		for k, v := c.Last(); k != nil; k, v = c.Prev() {
+			names = append(names, string(k))
+			if v != nil {
+				t.Fatalf("unexpected value: %v", v)
+			}
+		}
+		if !reflect.DeepEqual(names, []string{"foo", "baz", "bar"}) {
+			t.Fatalf("unexpected names: %+v", names)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func ExampleCursor() {
+	// Open the database.
+	db, err := bolt.Open(tempfile(), 0666, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.Remove(db.Path())
+
+	// Start a read-write transaction.
+	if err := db.Update(func(tx *bolt.Tx) error {
+		// Create a new bucket.
+		b, err := tx.CreateBucket([]byte("animals"))
+		if err != nil {
+			return err
+		}
+
+		// Insert data into a bucket.
+		if err := b.Put([]byte("dog"), []byte("fun")); err != nil {
+			log.Fatal(err)
+		}
+		if err := b.Put([]byte("cat"), []byte("lame")); err != nil {
+			log.Fatal(err)
+		}
+		if err := b.Put([]byte("liger"), []byte("awesome")); err != nil {
+			log.Fatal(err)
+		}
+
+		// Create a cursor for iteration.
+		c := b.Cursor()
+
+		// Iterate over items in sorted key order. This starts from the
+		// first key/value pair and updates the k/v variables to the
+		// next key/value on each iteration.
+		//
+		// The loop finishes at the end of the cursor when a nil key is returned.
+		for k, v := c.First(); k != nil; k, v = c.Next() {
+			fmt.Printf("A %s is %s.\n", k, v)
+		}
+
+		return nil
+	}); err != nil {
+		log.Fatal(err)
+	}
+
+	if err := db.Close(); err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// A cat is lame.
+	// A dog is fun.
+	// A liger is awesome.
+}
+
+func ExampleCursor_reverse() {
+	// Open the database.
+	db, err := bolt.Open(tempfile(), 0666, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.Remove(db.Path())
+
+	// Start a read-write transaction.
+	if err := db.Update(func(tx *bolt.Tx) error {
+		// Create a new bucket.
+		b, err := tx.CreateBucket([]byte("animals"))
+		if err != nil {
+			return err
+		}
+
+		// Insert data into a bucket.
+		if err := b.Put([]byte("dog"), []byte("fun")); err != nil {
+			log.Fatal(err)
+		}
+		if err := b.Put([]byte("cat"), []byte("lame")); err != nil {
+			log.Fatal(err)
+		}
+		if err := b.Put([]byte("liger"), []byte("awesome")); err != nil {
+			log.Fatal(err)
+		}
+
+		// Create a cursor for iteration.
+		c := b.Cursor()
+
+		// Iterate over items in reverse sorted key order. This starts
+		// from the last key/value pair and updates the k/v variables to
+		// the previous key/value on each iteration.
+		//
+		// The loop finishes at the beginning of the cursor when a nil key
+		// is returned.
+		for k, v := c.Last(); k != nil; k, v = c.Prev() {
+			fmt.Printf("A %s is %s.\n", k, v)
+		}
+
+		return nil
+	}); err != nil {
+		log.Fatal(err)
+	}
+
+	// Close the database to release the file lock.
+	if err := db.Close(); err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// A liger is awesome.
+	// A dog is fun.
+	// A cat is lame.
+}