There are such Entity (Store and Check):

Shops

@Entity(indices = {@Index(value = {"inn"}, unique = true)}) public class Shops { @PrimaryKey(autoGenerate = true) public int id; public String name; public String inn; }

Receipts

 @Entity(foreignKeys = @ForeignKey( entity = Shops.class, parentColumns = "id", childColumns = "shop_id") ) public class Receipts { @PrimaryKey(autoGenerate = true) public int id; public Long date; public double totalSum; public int shop_id; }

You need to get a list of Receipts , in which shop_id will be replaced by Shops.name . Those. perform table joins.

Of

Source

Receive

Destination

On pure SQLite, the query would be:

 SELECT Receipts.id, Receipts.date, Receipts.totalSum, Shops.name FROM Receipts INNER JOIN Shops ON Shops.id = Receipts.shop_id;

Those. Dao view:

 @Query("SELECT Receipts.id, Receipts.date, Receipts.totalSum, Shops.name " + "FROM Receipts " + "INNER JOIN Shops ON Shops.id = Receipts.shop_id;") public List<Receipts> getReceiptsWithShops();

However, List<Receipts> not suitable as a return data type.

What is the best way to act when implementing through Room? Create a new Receipts class?

  • Create a new class ReceiptWithShop . Relation Documentation - eugeneek

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