Question

因此它不会在具有外键User的表 Task 中插入数据。

这是任务类：

package com.example.gencode.execomtodolist.model;

import com.j256.ormlite.field.DatabaseField;
import com.j256.ormlite.table.DatabaseTable;


@DatabaseTable
public class Task{

@DatabaseField(generatedId = true)
private Long id;

@DatabaseField
private String title;

@DatabaseField
private String description;

@DatabaseField
private boolean done;

@DatabaseField (foreign = true, foreignAutoRefresh = true)
private User user;

public Task(){

}

public Task(User user, String title, String description, boolean done) {
    this.user = user;
    this.title = title;
    this.description = description;
    this.done = done;
}

@Override
public String toString() {
    return " " + title;
}

public Long getId() {
    return id;
}

public String getTitle() {
    return title;
}

public String getDescription() {
    return description;
}

public User getUser() { return user; }

public void setUser(User user) { this.user = user; }

public boolean isDone() { return done; }
}

这是用户类：

package com.example.gencode.execomtodolist.model;

import com.j256.ormlite.dao.ForeignCollection;
import com.j256.ormlite.field.DatabaseField;
import com.j256.ormlite.field.ForeignCollectionField;
import com.j256.ormlite.table.DatabaseTable;
import java.util.Collection;

@DatabaseTable
public class User{

@DatabaseField(generatedId = true)
private Long id;

@DatabaseField
private String username;

@DatabaseField
private String password;

@ForeignCollectionField
private ForeignCollection<Task> userTasks;

public User(){

}

public User(String username, String password) {
    this.username = username;
    this.password = password;
}

@Override
public String toString() {
    return " " + username + " " + password;
}

public String getUsername() {
    return username;
}

public Long getId() {
    return id;
}

public String getPassword() {
    return password;
}

public Collection<Task> getUserTasks() { return userTasks; }

}

当我尝试这个时：

    private void insertUsers(){
    User user1 = new User("Djavo", "666");
    User user2 = new User("Martel", "123");

    userDao.create(user1);
    userDao.create(user2);

    Task task1 = new Task(user1, "naslov1", "opis232", false);
    Task task2 = new Task(user1, "naslov2", "opis3232", false);

    taskDao.create(task1);
    taskDao.create(task2);

    Log.d("ORMLITEDEMO", "User1 and User2 and Task1 and Task2 CREATED!!!");
}

发生错误：

引起：java.sql.SQLException：插入数据库失败：INSERT INTO task（description，user_id，title，done）VALUES （？，？，？，？）

我是Android的初学者，特别是在ORMLite，所以请帮忙。

Answer 1

好的，我发现了什么问题。因为我在Task类中更改了Task表，所以需要重新创建数据库以提交更改。所以我做的是删除我的数据库，然后再次创建它。它现在有效。

不要将数据插入到ORMLite中具有一对多实现的表中

1 个答案: