我可以在房间数据库中自动增加ID，但是在刷新数据库时它会显示两倍 [英] I can auto increment id in room database but when refresh database it's shows double

问题描述

在我的应用程序中，我首先使用改造从服务器上获取数据，然后将其保存在房间数据库表中，然后在recyclerview中显示，但是当我使用ID作为主键时，它仅显示一个数据，则此ID我注释为autoGenerate = true然后它显示了我放入服务器的所有数据，但是当我重新打开我的应用程序时，它显示的是双重数据(这意味着首先我在服务器中有3个数据，该应用程序显示了3个数据，但是当我重新打开或刷新数据库时，它显示了6个数据，每次刷新时它都会增加).但是我希望此ID增加，但数据不会增加，这意味着服务器具有3个数据并将其存储在会议室数据库表中.

In my app firstly i am fetching data from server using retrofit then it's saved in room database table then it shows in recyclerview but when i using a id as a primary key it's show only one data then this id i annotat autoGenerate = true then it's show all data which i put in server but when i reopen my app,it's show double data(this mean firstly i have 3 data in server,this app show 3 data but when i reopen or refresh my database it's show 6 data ,every time in refresh it's increasing).but i want this id will be increase but data will be not increase that's mean server have 3 data and it's store in room database table.

Movie.kt

@Entity(tableName = "movie_table")
data class Movie(
@PrimaryKey(autoGenerate = true)
var id: Int = 0,
@SerializedName("Title")
@Expose
val title: String,
@SerializedName("Year")
@Expose
val Year: Int,
@SerializedName("Genre")
@Expose
val genre: String,
@SerializedName("Language")
@Expose
val language: String,
@SerializedName("Country")
@Expose
val country: String,
@SerializedName("Poster")
@Expose
val poster: String,
@SerializedName("Plot")
@Expose
val plot:String
)

MovieDao.kt

MovieDao.kt

@Dao
interface MovieDao {
@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insertMovie(movie: Movie)

@Query("SELECT * FROM movie_table")
suspend fun getAllMovieDB(): List<Movie>

@Query("SELECT * FROM movie_table WHERE title LIKE :title")
suspend fun getSearchMovieDB(title: String): List<Movie>
}

MovieDatabase.kt

MovieDatabase.kt

@Database(
entities = [Movie::class],
version = 1)
abstract class MovieDatabase: RoomDatabase() {
abstract fun getMovieDao(): MovieDao

companion object{
    @Volatile
    private var instance : MovieDatabase? = null
    private val LOCK = Any()
    operator fun invoke(context: Context) = instance
        ?: synchronized(LOCK){
            instance
                ?: buildDatabase(context).also{
                    instance = it
                }
        }
    private fun buildDatabase(context: Context) = Room.databaseBuilder(
        context.applicationContext,
        MovieDatabase::class.java,
        "movieDatabase"
    ).build()
}
}

Repository.kt

Repository.kt

class Repository(context: Context) {
private val movieDao: MovieDao = MovieDatabase.invoke(context).getMovieDao()
private val movieCall = MovieApiClient.movieApi
suspend fun insertMovie(movie: Movie) {
    movieDao.insertMovie(movie)
}
suspend fun searchData(title: String): List<Movie> {
    return movieDao.getSearchMovieDB(title)
}
suspend fun getAllMovieDB(): List<Movie> {
    return movieDao.getAllMovieDB().also {
        getAllMovieFromServer()
    }
}
private suspend fun getAllMovieFromServer() {
    try {
        val movieList = movieCall.getAllMovie()
        movieList.forEach {
            insertMovie(it)
        }
    } catch (exception: Throwable) {
    }
}
}

通过图像更好地理解(1)当id作为没有"autoGenerate ＝ true"的主键时，注释在此处输入图片描述

better understanding with image (1)when id as a primary key without "autoGenerate = true" annotate enter image description here

(2)当id为"autoGenerate = true"的主键时；注释在此处输入图片描述

(2)when id as a primary key with "autoGenerate = true" annotate enter image description here

在没有重复数据的情况下如何增加ID?如何解决此问题?请帮助我，谢谢.

How can I increase id without double data, How can i fix this? Please help me, Thank you.

推荐答案

好像没有从服务器获取电影ID.这意味着您无法知道数据库中何时已存在特定电影，这就是为什么该电影被复制"的原因.

Looks like you are not fetching the movie ID from the server. This means that there is no way for you to know when a specific movie already exists in your DB, which is why it gets "duplicated".

要解决此问题，只需确保也从服务器获取影片ID，以及所有其他影片数据.并删除"autoGenerate = true"因为您将使用自己的ID.

To fix this simply make sure to fetch the movie ID from the server, too, along with all the other movie data. And remove the "autoGenerate = true" since you'll be using your own IDs.

这将确保从服务器获取数据库中已存在的电影时，插入查询中将存在冲突，并且由于您使用了(onConflict = OnConflictStrategy.REPLACE)"，它将使用新数据更新行.

This will ensure that when a movie that already exists in your DB is fetched from the server, there will be a conflict in the insert query, and since you used "(onConflict = OnConflictStrategy.REPLACE)" it will update the row with the new data.

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