| 876 | } |
| 877 | |
| 878 | func ExampleCursor() { |
| 879 | // Open the database. |
| 880 | db, err := bolt.Open(tempfile(), 0600, nil) |
| 881 | if err != nil { |
| 882 | log.Fatal(err) |
| 883 | } |
| 884 | defer os.Remove(db.Path()) |
| 885 | |
| 886 | // Start a read-write transaction. |
| 887 | if err := db.Update(func(tx *bolt.Tx) error { |
| 888 | // Create a new bucket. |
| 889 | b, err := tx.CreateBucket([]byte("animals")) |
| 890 | if err != nil { |
| 891 | return err |
| 892 | } |
| 893 | |
| 894 | // Insert data into a bucket. |
| 895 | if err := b.Put([]byte("dog"), []byte("fun")); err != nil { |
| 896 | log.Fatal(err) |
| 897 | } |
| 898 | if err := b.Put([]byte("cat"), []byte("lame")); err != nil { |
| 899 | log.Fatal(err) |
| 900 | } |
| 901 | if err := b.Put([]byte("liger"), []byte("awesome")); err != nil { |
| 902 | log.Fatal(err) |
| 903 | } |
| 904 | |
| 905 | // Create a cursor for iteration. |
| 906 | c := b.Cursor() |
| 907 | |
| 908 | // Iterate over items in sorted key order. This starts from the |
| 909 | // first key/value pair and updates the k/v variables to the |
| 910 | // next key/value on each iteration. |
| 911 | // |
| 912 | // The loop finishes at the end of the cursor when a nil key is returned. |
| 913 | for k, v := c.First(); k != nil; k, v = c.Next() { |
| 914 | fmt.Printf("A %s is %s.\n", k, v) |
| 915 | } |
| 916 | |
| 917 | return nil |
| 918 | }); err != nil { |
| 919 | log.Fatal(err) |
| 920 | } |
| 921 | |
| 922 | if err := db.Close(); err != nil { |
| 923 | log.Fatal(err) |
| 924 | } |
| 925 | |
| 926 | // Output: |
| 927 | // A cat is lame. |
| 928 | // A dog is fun. |
| 929 | // A liger is awesome. |
| 930 | } |
| 931 | |
| 932 | func ExampleCursor_reverse() { |
| 933 | // Open the database. |