forked from mirror/ledisdb
71 lines
1.3 KiB
Go
71 lines
1.3 KiB
Go
// +build lmdb
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package mdb
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import (
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"fmt"
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"io/ioutil"
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"os"
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)
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// Most mdb functions/methods can return errors. This example ignores errors
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// for brevity. Real code should check all return values.
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func Example() {
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// create a directory to hold the database
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path, _ := ioutil.TempDir("", "mdb_test")
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defer os.RemoveAll(path)
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// open the db
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env, _ := NewEnv()
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env.SetMapSize(1 << 20) // max file size
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env.Open(path, 0, 0664)
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defer env.Close()
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txn, _ := env.BeginTxn(nil, 0)
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dbi, _ := txn.DBIOpen(nil, 0)
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defer env.DBIClose(dbi)
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txn.Commit()
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// write some data
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txn, _ = env.BeginTxn(nil, 0)
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num_entries := 5
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for i := 0; i < num_entries; i++ {
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key := fmt.Sprintf("Key-%d", i)
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val := fmt.Sprintf("Val-%d", i)
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txn.Put(dbi, []byte(key), []byte(val), 0)
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}
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txn.Commit()
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// inspect the database
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stat, _ := env.Stat()
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fmt.Println(stat.Entries)
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// scan the database
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txn, _ = env.BeginTxn(nil, RDONLY)
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defer txn.Abort()
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cursor, _ := txn.CursorOpen(dbi)
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defer cursor.Close()
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for {
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bkey, bval, err := cursor.Get(nil, nil, NEXT)
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if err == NotFound {
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break
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}
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if err != nil {
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panic(err)
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}
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fmt.Printf("%s: %s\n", bkey, bval)
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}
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// random access
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bval, _ := txn.Get(dbi, []byte("Key-3"))
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fmt.Println(string(bval))
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// Output:
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// 5
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// Key-0: Val-0
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// Key-1: Val-1
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// Key-2: Val-2
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// Key-3: Val-3
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// Key-4: Val-4
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// Val-3
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}
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