多字段-Put_fields,Get_fields,FindKeysByField

db/db_impl.h

@@ -42,6 +42,11 @@ class DBImpl : public DB {
   Status Write(const WriteOptions& options, WriteBatch* updates) override;
   Status Get(const ReadOptions& options, const Slice& key,
              std::string* value) override;
+  Status Put_fields(const WriteOptions& options, const Slice& key,
+                     const FieldArray& fields) override;
+  Status Get_fields(const ReadOptions& options, const Slice& key,
+                     FieldArray* fields) override;
+  std::vector<std::string> FindKeysByField(leveldb::DB* db, Field &field) override;
   Iterator* NewIterator(const ReadOptions&) override;
   const Snapshot* GetSnapshot() override;
   void ReleaseSnapshot(const Snapshot* snapshot) override;