1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
This is an implementation of the [LevelDB key/value database](http:code.google.com/p/leveldb) in the [Go programming language](http:golang.org).
[](https://travis-ci.org/syndtr/goleveldb)
Installation
-----------
go get github.com/syndtr/goleveldb/leveldb
Requirements
-----------
* Need at least `go1.4` or newer.
Usage
-----------
Create or open a database:
```go
db, err := leveldb.OpenFile("path/to/db", nil)
...
defer db.Close()
...
```
Read or modify the database content:
```go
// Remember that the contents of the returned slice should not be modified.
data, err := db.Get([]byte("key"), nil)
...
err = db.Put([]byte("key"), []byte("value"), nil)
...
err = db.Delete([]byte("key"), nil)
...
```
Iterate over database content:
```go
iter := db.NewIterator(nil, nil)
for iter.Next() {
// Remember that the contents of the returned slice should not be modified, and
// only valid until the next call to Next.
key := iter.Key()
value := iter.Value()
...
}
iter.Release()
err = iter.Error()
...
```
Seek-then-Iterate:
```go
iter := db.NewIterator(nil, nil)
for ok := iter.Seek(key); ok; ok = iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
```
Iterate over subset of database content:
```go
iter := db.NewIterator(&util.Range{Start: []byte("foo"), Limit: []byte("xoo")}, nil)
for iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
```
Iterate over subset of database content with a particular prefix:
```go
iter := db.NewIterator(util.BytesPrefix([]byte("foo-")), nil)
for iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
```
Batch writes:
```go
batch := new(leveldb.Batch)
batch.Put([]byte("foo"), []byte("value"))
batch.Put([]byte("bar"), []byte("another value"))
batch.Delete([]byte("baz"))
err = db.Write(batch, nil)
...
```
Use bloom filter:
```go
o := &opt.Options{
Filter: filter.NewBloomFilter(10),
}
db, err := leveldb.OpenFile("path/to/db", o)
...
defer db.Close()
...
```
Documentation
-----------
You can read package documentation [here](http:godoc.org/github.com/syndtr/goleveldb).
|
