Room persistence library @Query not working

Question

I have also uploaded the whole project to GitHub, the code and the main line of code the request the query is line 144 in DetailFragment.java.

I am trying to query ingredients from the table with the id, the query is returning a null result. the same query is working well but without LIKE (:id) LIMIT 1, but giving all the rows.

@Query("SELECT ingredients FROM recipe_db WHERE id LIKE (:id) LIMIT 1")
String getRecipeIngredients(List<Integer> id);

I have tried:

1. = instead of LIKE
2. :ids without ()
3. single Integer/int id
4. checked Database itself if the desired id doesn't exist.

recipe_db code

@Entity(tableName = DATABASE_NAME)
public class Recipe implements Parcelable {

@ColumnInfo(name = "image_url")
private String image;

@ColumnInfo(name = "servings")
private int servings;

@ColumnInfo(name = "steps")
private List<Steps> steps;

@ColumnInfo(name = "ingredients")
private List<Ingredient> ingredients;

@NonNull
@ColumnInfo(name = "name")
private String name;

@PrimaryKey
@ColumnInfo(name = "id")
private int id;

public Recipe(@NonNull String image, int servings, List<Steps> steps
        , List<Ingredient> ingredients, @NonNull String name, int id) {
    this.image = image;
    this.servings = servings;
    this.steps = steps;
    this.ingredients = ingredients;
    this.name = name;
    this.id = id;
}


public String getImage() {
    return image;
}

public int getServings() {
    return servings;
}

public List<Steps> getSteps() {
    return steps;
}

public List<Ingredient> getIngredients() {
    return ingredients;
}

public String getName() {
    return name;
}

public int getId() {
    return id;
}

public static class Steps {
    @SerializedName("thumbnailURL")
    private String thumbnailurl;
    @SerializedName("videoURL")
    private String videourl;
    @SerializedName("shortDescription")
    private String shortdescription;
    private String description;
    private int id;

    public String getThumbnailurl() {
        return thumbnailurl;
    }

    public String getVideourl() {
        return videourl;
    }

    public String getDescription() {
        return description;
    }

    public String getShortdescription() {
        return shortdescription;
    }

    public int getId() {
        return id;
    }

    public void setThumbnailurl(String thumbnailurl) {
        this.thumbnailurl = thumbnailurl;
    }

    public void setVideourl(String videourl) {
        this.videourl = videourl;
    }

    public void setShortdescription(String shortdescription) {
        this.shortdescription = shortdescription;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public void setId(int id) {
        this.id = id;
    }
}

public static class Ingredient {
    private String ingredient;
    private String measure;

    @Ignore
    private float quantity;

    private String str_quantity;

    public String getIngredient() {
        return ingredient;
    }

    public String getMeasure() {
        return measure;
    }

    public float getQuantity() {
        return quantity;
    }

    public void setIngredient(String ingredient) {
        this.ingredient = ingredient;
    }

    public void setMeasure(String measure) {
        this.measure = measure;
    }

    public void setQuantity(float quantity) {
        this.quantity = quantity;
    }

    public String getStr_quantity() {
        return String.valueOf(quantity);
    }

    public void setStr_quantity(String str_quantity) {
        this.str_quantity = str_quantity;
    }
}


@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(this.image);
    dest.writeInt(this.servings);
    dest.writeList(this.steps);
    dest.writeList(this.ingredients);
    dest.writeString(this.name);
    dest.writeInt(this.id);
}

protected Recipe(Parcel in) {
    this.image = in.readString();
    this.servings = in.readInt();
    this.steps = new ArrayList<Steps>();
    in.readList(this.steps, Steps.class.getClassLoader());
    this.ingredients = new ArrayList<Ingredient>();
    in.readList(this.ingredients, Ingredient.class.getClassLoader());
    this.name = in.readString();
    this.id = in.readInt();
}

public static final Parcelable.Creator<Recipe> CREATOR = new Parcelable.Creator<Recipe>() {
    @Override
    public Recipe createFromParcel(Parcel source) {
        return new Recipe(source);
    }

    @Override
    public Recipe[] newArray(int size) {
        return new Recipe[size];
    }
};
}

Answer 1

I have asked My Mentor "ANTHONY" in Android Nanodegree course and here his answer

This is happening because the SQL is setup incorrectly.

@Query("SELECT ingredients FROM recipe_db WHERE id LIKE :id LIMIT 1")

You want to set it up so it matches the passed in ID. The LIKE clause works differently and uses pattern matching symbols.

Answer 2

Try this way query..

@Query("SELECT ingredients FROM recipe_db WHERE id LIKE :id LIMIT 1")
String getRecipeIngredients(List<Integer> id);

if you want then try on name and other fields.