读写操作 - Reads And Writes

读写操作 - Reads And Writes

数据库提供Put, Delete, Get这些方法来修改和查询数据库。比如，以下操作时将存储在key1的值移动到key2中去：

  2. 1. std::string value;
  3. 2. leveldb::Status s = db->Get(leveldb::ReadOptions(), key1, &value);
  4. 3. if (s.ok()) s = db->Put(leveldb::WriteOptions(), key2, value);
  5. 4. if (s.ok()) s = db->Delete(leveldb::WriteOptions(), key1);