Android机房SELECT * WHERE返回所有记录

Question

I've got an Android Room database setup and followed some tutorials with which I'm trying to extend what I've made. I have gotten a few queries to work but when I try to use a SELECT * WHERE query it returns all the records in the table not just the records with the expected ID.

The Query in the DAO

@Query("SELECT * FROM weapon_table WHERE fighter_id = :fighter_id" )
LiveData<List<Weapon>> getFighterWeapons(long fighter_id);

The Record Object

@Entity(tableName = "weapon_table",
        foreignKeys = {
                @ForeignKey(entity = com.Database.Fighter.class,
                        parentColumns = "fighter_id",
                        childColumns = "fighter_id"),
        })
public class Weapon
{
    @NonNull
    String weapon_name;
    @NonNull
    @PrimaryKey(autoGenerate = true)
    long weapon_id;
    @NonNull
    long fighter_id;


    public Weapon(String weapon_name, long fighter_id)
    {
        this.weapon_name = weapon_name;
        this.fighter_id = fighter_id;
    }

    public long getWeapon_id()
    {
        return weapon_id;
    }

    public void setWeapon_id(long weapon_id)
    {
        this.weapon_id = weapon_id;
    }

    public String getWeapon_name()
    {
        return weapon_name;
    }

    public void setWeapon_name(String weapon_name)
    {
        this.weapon_name = weapon_name;
    }

    public long getFighter_id()
    {
        return fighter_id;
    }

    public void setFighter_id(long fighter_id)
    {
        this.fighter_id = fighter_id;
    }
}

When I call the following code all records are printed to the debug console but the current ID is also printed and stays the same in all cases.

   public void onClickAddWeapon(View view)
{
    List<Weapon> weapons = mWeaponViewModel.getFighterWeapons(fighter.getFighter_id()).getValue();
    for(Weapon weapon: weapons )
    {
        Log.d("WEAPONDEBUG", "WEAPONNAME/ID: " +weapon.getWeapon_name() +'/'+ weapon.getFighter_id() );
        Log.d("WEAPONDEBUG", "FIGHTERID: "+ fighter.getFighter_id() );

    }
}

Answer 1

Fix was fairly simple , I had followed this google code labs tutorial and when I tried to extend it I forgot to actually assign the result of the query to the list held in the repository file. Thanks for the suggestions they put me in the right direction.

  LiveData<List<Weapon>> getFighterWeapons(long fighter_id)
    {
        mWeaponDao.getFighterWeapons(fighter_id);
        return mAllWeapons;
    }

replaced with

LiveData<List<Weapon>> getFighterWeapons(long fighter_id)
{
    mAllWeapons = mWeaponDao.getFighterWeapons(fighter_id);
    return mAllWeapons;
}

Answer 2

your code should be working, but I think that the problem is defining with foreign keys. `

parentColumns = "fighter_id",

childColumns = "fighter_id"

can you remove it and try?

                    `

Answer 3

Try this

@Query("SELECT * FROM weapon_table WHERE fighter_id IN (:fighter_id)" )
LiveData<List<Weapon>> getFighterWeapons(long fighter_id);