CODEWITHSUNDEEP
androidandroid-room
ant2009
ant2009

Reputation: 22526

Inheriting from a room DAO interface

I have following interface where I have created the standard crud methods and annotated the methods with insert, update, and delete.

interface BaseDao<T> {
    @Insert
    fun insert(table: T): Single<Long>

    @Insert
    fun insert(vararg table: T): Single<List<Long>>

    @Update
    fun update(table: T): Single<Int>

    @Delete
    fun delete(table: T): Single<Int>
}

I then create a interface for the DAO

@Dao
interface WeatherDao : BaseDao<WeatherTable> {

    override fun insert(table: WeatherTable): Single<Long>

    override fun insert(vararg table: WeatherTable): Single<List<Long>>

    override fun update(table: WeatherTable): Single<Int>

    override fun delete(table: WeatherTable): Single<Int>

    @Query("SELECT * FROM weatherTable")
    fun getAllWeather(): Single<List<WeatherTable>>

    @Query("SELECT * FROM weatherTable WHERE id = :id LIMIT 1")
    fun getWeatherById(id: Long): Single<WeatherTable>

    @Query("SELECT count(*) FROM weatherTable")
    fun count(): Single<Int>
}

When I compile I get a lot of error like this following:

error: An abstract DAO method must be annotated with one and only one of the following annotations: Insert,Delete,Query,Update,RawQuery
    public abstract io.reactivex.Single<java.lang.Long> delete(@org.jetbrains.annotations.NotNull()

Because when I inherited from the interface. I have to manually add the @Insert, @Update, and @Delete.

Just wondering why these annontations are added automatically in the my WeatherDao interface.

So I now have to manually add them like this:

@Dao
interface WeatherDao : BaseDao<WeatherTable> {

    @Insert
    override fun insert(table: WeatherTable): Single<Long>

    @Insert
    override fun insert(vararg table: WeatherTable): Single<List<Long>>

    @Update
    override fun update(table: WeatherTable): Single<Int>

    @Delete
    override fun delete(table: WeatherTable): Single<Int>

    @Query("SELECT * FROM weatherTable")
    fun getAllWeather(): Single<List<WeatherTable>>

    @Query("SELECT * FROM weatherTable WHERE id = :id LIMIT 1")
    fun getWeatherById(id: Long): Single<WeatherTable>

    @Query("SELECT count(*) FROM weatherTable")
    fun count(): Single<Int>
}

Just wondering if I am using this wrong:

Upvotes: 1

Views: 744

Answers (1)

Henrique Vasconcellos
Henrique Vasconcellos

Reputation: 1183

Following this google repo, you are not doing the abstractation correctly. To sum up, you do not need to have the inserts/updates/deletes in your @Dao Interface and it should be abstract.

interface BaseDao<T> {

    /**
     * Insert an object in the database.
     *
     * @param obj the object to be inserted.
     */
    @Insert
    fun insert(obj: T)

    /**
     * Insert an array of objects in the database.
     *
     * @param obj the objects to be inserted.
     */
    @Insert
    fun insert(vararg obj: T)

    /**
     * Update an object from the database.
     *
     * @param obj the object to be updated
     */
    @Update
    fun update(obj: T)

    /**
     * Delete an object from the database
     *
     * @param obj the object to be deleted
     */
    @Delete
    fun delete(obj: T)
}

@Entity(tableName = "data")
data class Data(@PrimaryKey val id: String, val value: String)

@Dao
abstract class DataDao : BaseDao<Data>() {

    /**
     * Get all data from the Data table.
     */
    @Query("SELECT * FROM Data")
    abstract fun getData(): List<Data>
}

Upvotes: 1

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