Cascade delete based on @ForeignKey in Android Rooms ORM

I have two entities DBList adnd DBListContent. With one to many relationship between DBList and DBListContent.

DBList

DBListContent

DBList

DBListContent

Here is the DBList class

DBList

@Entity(tableName = "lists")
public class DBList {
@PrimaryKey
private String listId;
private String title;
private String createdDateTime;
}


Here is the DBListContent

DBListContent

@Entity(tableName = "listContents")
public class DBListContent {
@PrimaryKey
public String listContentId;
public String content;
public String lastEditedBy;
public String lastEditedDateTime;

@ForeignKey(entity = DBList.class, parentColumns = "listId", childColumns = "dbListId", onDelete = CASCADE)
public String dbListId;
}


When I delete a row in lists table, the corresponding rows in the listContents table are not deleted.

lists

listContents

I deleted the rows using the following Dao methods

@Delete
void deleteLists(List<DBList> dbLists);

@Query("delete from lists")
void deleteLists();


I know I am missing something pretty obvious. Please guide me in this.

1 Answer
1

I don't know it's too late to answer your question, but the mistake you have is to put @ForeignKey in a field.

@ForeignKey

The @ForeignKeys MUST to go in table declaration.

@ForeignKeys

Your code should look like that.

@Entity(tableName = "listContents",foreignKeys ={
@ForeignKey(onDelete = CASCADE,entity = DBList.class,
parentColumns = "listId",childColumns = "dbListId")},
indices = {
@Index("dbListId"),
})
public class DBListContent {
@PrimaryKey
public String listContentId;
public String content;
public String lastEditedBy;
public String lastEditedDateTime;
public String dbListId;
}


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