imported>CCC2012：/* 特徵 */ wikify

2025-07-18T17:38:03Z

特徵： wikify

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{{Infobox software
|name = LevelDB
|title = LevelDB
|logo = 
|screenshot = 
|caption =
|collapsible =
|author =
|developer = [[Google]]
|released = {{Start date and age|2012|05}}
|discontinued =
|latest release version = {{LSR/wikidata}}
|programming language = [[C++]]
|operating system = [[跨平台]]
|platform =
|size =
|language =
|genre = 嵌入[[數據庫]]編程庫
|license = [[BSD许可证]]
}}

'''{{lang|en|LevelDB}}'''是一個由[[Google公司]]所研發的[[键-值存储]][[嵌入式系統|嵌入式]][[數據庫管理系統]]編程庫，<ref>{{Cite web |url=http://rdc.taobao.com/blog/cs/wp-content/plugins/leveldb%E5%AE%9E%E7%8E%B0%E8%A7%A3%E6%9E%90.pdf |title=leveldb實現解析 |accessdate=2017-09-05 |archive-date=2012-01-31 |archive-url=https://web.archive.org/web/20120131105110/http://rdc.taobao.com/blog/cs/wp-content/plugins/leveldb%E5%AE%9E%E7%8E%B0%E8%A7%A3%E6%9E%90.pdf |dead-url=no }}</ref> 以[[開源軟體|開源]]的[[BSD許可證]]發佈。<ref>{{Cite web |url=http://google-opensource.blogspot.com/2011/07/leveldb-fast-persistent-key-value-store.html |title=LevelDB: A Fast Persistent Key-Value Store |accessdate=2011-08-07 |archive-date=2016-03-26 |archive-url=https://web.archive.org/web/20160326154020/http://google-opensource.blogspot.com/2011/07/leveldb-fast-persistent-key-value-store.html |dead-url=no }}</ref>

== 特徵 ==
* 高性能 <ref>{{Cite web |url=http://leveldb.googlecode.com/svn/trunk/doc/benchmark.html |title=LevelDB Benchmarks |accessdate=2011-08-07 |archive-date=2011-08-20 |archive-url=https://web.archive.org/web/20110820001028/http://leveldb.googlecode.com/svn/trunk/doc/benchmark.html |dead-url=yes }}</ref>
* 簡單的體系結構：只支持API调用，不支持[[SQL]]語言
* [[自由軟件]]和[[開放原始碼軟件]]
* 數據支持被[[Snappy]]函式庫壓縮<ref>{{Cite web |url=http://code.google.com/p/snappy/ |title=A fast compressor/decompressor |accessdate=2011-07-30 |archive-date=2015-08-22 |archive-url=https://web.archive.org/web/20150822162211/https://code.google.com/p/snappy/ |dead-url=no }}</ref>，以減少Disk I/O提升效能

== 例子 ==
儲存鍵／值對，和查詢鍵的值：

<syntaxhighlight lang=cpp>
#include "leveldb/db.h"
#include <iostream>

using namespace std;

int main(){
leveldb::DB *db;
leveldb::Options options;

options.create_if_missing = true;

// 開啟數據庫
leveldb::DB::Open(options, "/tmp/testdb", &db);

// 鍵 = MyKey29，值 = "Hello World!"
string key = "MyKey29", value = "Hello World!", result;

// 儲存鍵／值對
db->Put(leveldb::WriteOptions(), key, value);

// 查詢 MyKey29 鍵的值
db->Get(leveldb::ReadOptions(), key, &result);

// 輸出值到屏幕
cout << "result = " << result << endl;

// 關閉數據庫
delete db;

return 0;
}
</syntaxhighlight>

=== 執行結果 ===
(LevelDB安裝目錄為：leveldb-read-only)<ref>{{Cite web |url=http://code.google.com/p/leveldb/source/checkout |title=Source Checkout - LevelDB |accessdate=2011-08-06 |archive-date=2015-03-18 |archive-url=https://web.archive.org/web/20150318200509/http://code.google.com/p/leveldb/source/checkout |dead-url=no }}</ref>
<pre>
% g++ test.cc -Ileveldb-read-only/include -Lleveldb-read-only -lleveldb -lpthread
% ./a.out
result = Hello World!
</pre>

== RocksDB ==
2013年[[Facebook]]基於LevelDB開發出[[RocksDB]]，特別針對伺服器負載而優化。<ref>{{Cite web |url=http://rocksdb.org/ |title=RocksDB |accessdate=2014-01-25 |archive-date=2021-02-05 |archive-url=https://web.archive.org/web/20210205060559/https://rocksdb.org/ |dead-url=no }}</ref>

== 语言的绑定 ==
* [https://github.com/reeze/php-leveldb PHP LevelDB Extension] {{Wayback|url=https://github.com/reeze/php-leveldb |date=20201015052114 }}
* [https://github.com/carlopires/cpy-leveldb Python LevelDB Binding] {{Wayback|url=https://github.com/carlopires/cpy-leveldb |date=20201130083754 }}

== 參見 ==
* [[Berkeley DB]]
* [[Apache Derby]]

== 参考文献 ==
{{Reflist|2}}

== 外部連結 ==
* [https://archive.today/20130426121503/http://leveldb.googlecode.com/ LevelDB 開放原始碼計劃主頁]

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[[Category:嵌入式資料庫]]
[[Category:2011年软件]]
[[Category:Google軟體]]
[[Category:開源資料庫管理系統]]
[[Category:跨平台軟體]]
[[Category:键-值数据库]]

LevelDB - 版本历史

imported>CCC2012：​/* 特徵 */ wikify

imported>CCC2012：/* 特徵 */ wikify