唯一约束失败的房间数据库Android [英] Unique constraint failed room database android

问题描述

我遇到了Room数据库的问题，当尝试使用我在Dao类中声明的insert方法将数据写入数据库时​​，出现此错误:

I'm facing a problem with Room database, when trying to use insert method that I declared in Dao Class to write a data into database this error shows up:

唯一约束失败

Unique constraint failed

有什么主意吗?

道课

@Dao
public interface TaskDao {

    @Query("SELECT * FROM task")
    List<Task> getall();

    @Insert
    void insert(Task task);

    @Delete
    void delete(Task task);
}

AppDatabase类

@Database(entities = {Task.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {
    public abstract TaskDao mTaskDao();
}

模型类

@Entity
public class Task {

    @PrimaryKey
    private int uid;

    @ColumnInfo(name = "task_name")
    private String mName;

    @ColumnInfo(name = "task_box")
    private Integer mBox;

    @ColumnInfo(name = "is_done")
    private Integer mIsDone;
}

推荐答案

我发现了这个错误，因为数据(在primaryKey中)没有唯一值，所以我将其自动生成，

I figure it out, that error because there is no unique value in data (in primaryKey) so I make it auto generated,

模型类

@Entity
public class Task {
    @PrimaryKey(autoGenerate = true)
    private int uid;
    ...
}

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