라이브러리 - Realm

Realm

 

✅ Realm이란?

---

Realm은 한 문장으로 말하면
👉 모바일 앱에 최적화된 객체(Object) 기반 로컬 데이터베이스.

 

“앱 안에 데이터를 빠르고 안정적으로 저장·조회하기 위해 만든 DB”

 

• 로컬 Realm DB
→ 앱 안에서만 쓰는 DB
→ 지금도 사용 가능

• MongoDB Realm / Device Sync
→ 서버 연동 + 동기화 서비스
→ 2024~2025년에 종료(EOL) 예고

👉 Realm = 로컬 DB 개념은 여전히 유효
👉 Sync 서비스만 종료

 

 

 

✅ 설치 및 사용법

---

설치

npm i realm

 

Usage

DB 연결

import Navigator from "@/components/navigator";
import { SplashScreen } from "expo-router";
import { useEffect, useState } from "react";
import Realm from "realm";

SplashScreen.preventAutoHideAsync();

const FeelingSchema = {
  name: "Feeling",
  properties: {
    _id: "int",
    emotion: "string",
    message: "string",
  },
  primaryKey: "_id",
};

export default function App() {
  const [ready, setReady] = useState(false);
  useEffect(() => {
    async function prepare() {
      try {
        const realm = await Realm.open({
          path: "nomadDiaryDB",
          schema: [FeelingSchema],
        });
        console.log(realm);
      } catch (e) {
        console.warn(e);
      } finally {
        setReady(true);
      }
    }
    prepare();
  }, []);

  useEffect(() => {
    if (ready) {
      SplashScreen.hideAsync();
    }
  }, [ready]);

  return <Navigator />;
}

 

Write

    realm?.write(() => {
      realm.create("Feeling", {
        _id: Date.now(),
        emotion: selectedEmotion,
        message: feelings,
      });
    });

 

Read

  const realm = useDB();
  useEffect(() => {
    const feelings = realm?.objects("Feeling");
    console.log(feelings);
  });

 

Filter

const happy = feelings?.filtered("emotion = '😊' ");

 

Delete

  const onPress = (id: number) => {
    realm?.write(() => {
      const feeling = realm.objectForPrimaryKey("Feeling", id);
      realm.delete(feeling);
    });
  };

 

addListener

  useEffect(() => {
    const results = realm?.objects<Feeling>("Feeling");
    results?.addListener((feelings, changes) => {
      setFeelings(feelings.sorted("_id", true));
    });
    return () => {
      results?.removeAllListeners();
    };
  }, [realm]);