Android ROOM：插入新数据时出现 FOREIGN KEY 约束失败（代码 787 SQLITE_CONSTRAINT FOREIGN KEY）

Question

我知道很多人都询问过这个 FOREIGN KEY 约束失败（代码 787 SQLITE_CONSTRAINT_FOREIGNKEY）错误，但我的问题略有不同。我有两个实体学生和记录。我可以添加学生，但是当我为那个学生添加相应的记录时，我收到了这个错误。首先我添加学生详细信息，然后添加学生记录详细信息。

学生POJO课

@Entity(tableName = "student_table")
public class Student {
    @PrimaryKey(autoGenerate = true)
    @ColumnInfo(name = "student_id")
    private int id;

    private String studentName;

    private String studentFatherName;

    private String studentSurname;

记录 POJO 类

    @Entity(tableName = "newRecord_table", indices = @Index("recordId"),
            foreignKeys = @ForeignKey(entity = Student.class, parentColumns = "student_id",childColumns = "recordId",
                    onDelete = ForeignKey.CASCADE, onUpdate = ForeignKey.CASCADE))

    public class NewRecord {

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

        public int recordId;
        public string address;
        public string mobile;

学生DAO课

@Dao
public interface StudentDAO {

    @Insert(onConflict = REPLACE)
    void addStudent (Student student);

    @Update
    void updateStudent (Student student);

    @Delete
    void deleteStudent (Student student);

    @Query("SELECT * FROM student_table ORDER BY studentName ASC")
    LiveData<List<Student>> getAllStudents();

    @Query("DELETE FROM student_table")
    void deleteAllStudents();
}

记录DAO类

@Dao
public interface NewRecordDAO {

    @Insert(onConflict = REPLACE)
    public void addRecord (NewRecord newRecord);

    @Update(onConflict = REPLACE)
    public void updateRecord (NewRecord newRecord);

    @Delete
    public void deleteRecord (NewRecord newRecord);

    @Query("DELETE FROM newRecord_table")
    void deleteAllRecords();

    @Query("SELECT * FROM newRecord_table ORDER BY NRdate DESC")
    LiveData<List<NewRecord>> getAllRecord();
}

学生知识库班

public class StudentRepository {
    private StudentDAO studentDAO;
    private LiveData<List<Student>> allStudents;

    public StudentRepository (Application application){
        StudentDatabase database = StudentDatabase.getInstance(application);
        studentDAO = database.studentDAO();
        allStudents = studentDAO.getAllStudents();
    }
     public void addStudent (Student student){
        new addStudentAsyncTask(studentDAO).execute(student);

     }
 public static class addStudentAsyncTask extends AsyncTask <Student,Void,Void>{
        private StudentDAO studentDAO;
        private addStudentAsyncTask (StudentDAO studentDAO){
            this.studentDAO = studentDAO;
        }
        @Override
        protected Void doInBackground(Student... students) {
            studentDAO.addStudent(students[0]);
            return null;
        }
    }

记录存储库类

public class NewRecordRepository {

    private NewRecordDAO newRecordDAO;
    private LiveData<List<NewRecord>> allRecords;
    private LiveData<List<NewRecord>> allRecordByStudent;

    public NewRecordRepository (Application application){
        StudentDatabase database = StudentDatabase.getInstance(application);
        newRecordDAO = database.newRecordDAO();
        allRecords = newRecordDAO.getAllRecord();

    }

    public void addRecord (NewRecord newRecord){
        new addRecordAsyncTask(newRecordDAO).execute(newRecord);
    }
 public static class addRecordAsyncTask extends AsyncTask<NewRecord,Void,Void> {
        private NewRecordDAO newRecordDAO;
        private addRecordAsyncTask (NewRecordDAO newRecordDAO){
            this.newRecordDAO = newRecordDAO;
        }
        @Override
        protected Void doInBackground(NewRecord... newRecords) {

// LOG shows: this is where it re direct me this is where the problem lies.
            newRecordDAO.addRecord(newRecords[0]);
            return null;
        }
    }

最后是数据库类

@Database(entities = {Student.class, NewRecord.class}, version = 1, exportSchema = false)
public abstract class StudentDatabase extends RoomDatabase {

    private static StudentDatabase instance;

    public abstract StudentDAO studentDAO();

    public abstract NewRecordDAO newRecordDAO();

    public static synchronized StudentDatabase getInstance(Context context){
        if ( instance == null ){
            instance = Room.databaseBuilder(context.getApplicationContext(),
                    StudentDatabase.class,"students_DB")
                    .fallbackToDestructiveMigration()
                    .build();
        }
        return instance;
    }

我的日志：

E/AndroidRuntime：致命异常：AsyncTask #4 进程：com.timelessfusionapps.hifztasmee，PID：12833 java.lang.RuntimeException：执行 doInBackground() 时出错 在 android.os.AsyncTask$3.done(AsyncTask.java:354) 在 java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:383) 在 java.util.concurrent.FutureTask.setException(FutureTask.java:252) 在 java.util.concurrent.FutureTask.run(FutureTask.java:271) 在 android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:245) 在 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 在 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 在 java.lang.Thread.run(Thread.java:764) 引起：android.database.sqlite.SQLiteConstraintException：FOREIGN KEY约束失败（代码787 SQLITE_CONSTRAINT_FOREIGNKEY） 在 android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native 方法） 在 android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:796) 在 android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788) 在 android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86) 在 androidx.sqlite.db.framework.FrameworkSQLiteStatement.executeInsert(FrameworkSQLiteStatement.java:51) 在 androidx.room.EntityInsertionAdapter.insert(EntityInsertionAdapter.java:64) 在 com.timelessfusionapps.hifztasmee.DOA.NewRecordDAO_Impl.addRecord(NewRecordDAO_Impl.java:242) 在 com.timelessfusionapps.hifztasmee.Repository.NewRecordRepository$addRecordAsyncTask.doInBackground(NewRecordRepository.java:61) 在 com.timelessfusionapps.hifztasmee.Repository.NewRecordRepository$addRecordAsyncTask.doInBackground(NewRecordRepository.java:54)

Answer 1

在调用addRecordnewRecord 对象时需要为添加的student_id 设置recordid。

如果有

    NewRecord n1 = new NewRecord();

    n1.address = "xxx";
    n1.mobile = "0000000000";
    n1.NRDate = "2020-01-01 10:30";
    newRecordRepository.addRecord(n1);

失败之类的

Caused by: android.database.sqlite.SQLiteConstraintException: FOREIGN KEY constraint failed (code 787 SQLITE_CONSTRAINT_FOREIGNKEY)

更改以提供适当的 recordId，例如

    NewRecord n1 = new NewRecord();
    n1.recordId = 1;
    n1.address = "xxx";
    n1.mobile = "0000000000";
    n1.NRDate = "2020-01-01 10:30";
    newRecordRepository.addRecord(n1);

工作。 1 可以展示测试，你需要合适的学生做真正的