java - 为什么我收到 'UNIQUE constraint failed' 错误

Question

我尝试将数据保存到 MyList 但收到此错误:UNIQUE 约束失败。我的错在哪里？

我的数据库

db.execSQL("CREATE TABLE IF NOT EXISTS \"Words\" (\n" +
                "\t\"Id\"\tINTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,\n" +
                "\t\"Name\"\tTEXT,\n" +
                "\t\"Mean\"\tTEXT\n" +
                ");");
        db.execSQL("CREATE TABLE IF NOT EXISTS \"MyList\" (\n" +
                "\t\"Id\"\tINTEGER NOT NULL,\n" +
                "\t\"Name\"\tTEXT,\n" +
                "\t\"Mean\"\tTEXT,\n" +
                "\tFOREIGN KEY(\"Id\") REFERENCES \"Words\"(\"Id\"),\n" +
                "\tPRIMARY KEY(\"Id\")\n" +
                ");");

InsertWordToMyList(插入从 Words 中提取的单词)

ifExists(如果单词存在于我的列表中则不插入)

FindWord(我的主表是 Words，因此我在 Words 中搜索数据(如果存在)，然后提取它)

public String InsertWordToList(DbConnection data,String kelime){


        Word yeni=null;
        SQLiteDatabase db= data.getWritableDatabase();

        ContentValues values= new ContentValues();

        String msg;
        Boolean bool = ifExists(data,kelime,db);
        if(bool){
            msg= "kelime zaten var";
        }
        else {
            yeni = FindWord(data, kelime, db);

            if(yeni!=null){
                Log.e("yeni id",Integer.toString(yeni.getId()));
                values.put("Id", yeni.getId());
                values.put("Name", yeni.getName());
                values.put("Mean", yeni.getMean());


                db.insertOrThrow("MyList", null, values);
                msg="kelime eklendi";
            }
            else msg="kelime databasede kayırlı değil";



        }
        db.close();
        return msg;

    }


    public Word FindWord(DbConnection data, String kelime, SQLiteDatabase db){

        Word w= new Word();
        //db= data.getWritableDatabase();



        Cursor c = db.rawQuery("SELECT * FROM Words WHERE Name = 'kelime'",null);

        if(c!=null){

            while (c.moveToNext()){
                w = new Word(c.getInt(c.getColumnIndex("Id"))
                        ,c.getString(c.getColumnIndex("Name"))
                        ,c.getString(c.getColumnIndex("Mean")));
            }

            return w;
        }
        else {

            return null;
        }
    }
    public Boolean ifExists (DbConnection data, String kelime, SQLiteDatabase db) {

        Word w=null;
        Cursor c = db.rawQuery("SELECT * FROM Mylist WHERE Name = 'kelime'",null);


        while (c.moveToNext()){
            w = new Word(c.getInt(c.getColumnIndex("Id"))
                    ,c.getString(c.getColumnIndex("Name"))
                    ,c.getString(c.getColumnIndex("Mean")));

        }

        if(w!=null) return true;
        else return false;
    }

InsertWordToMyList 的用法:

for(int i=0;i<get.size();i++){

                    msg=wordData.InsertWordToMyList(db,get.get(i));
                                  }

Answer 1

我不知道这是否能解决您的问题，但因为您的代码正在搜索字符串文字 'kelime' 而不是字符串参数 kelime .
更改方法 FindWord() 和 ifExists()，如下所示:

public Word FindWord(DbConnection data, String kelime, SQLiteDatabase db) {
    Word w = null;
    Cursor c = db.rawQuery("SELECT * FROM Words WHERE Name = ?", new String[] {kelime});
    if (c.moveToNext()) {
        w = new Word(c.getInt(c.getColumnIndex("Id"))
                , c.getString(c.getColumnIndex("Name"))
                , c.getString(c.getColumnIndex("Mean")));
    }
    c.close();
    return w;
}

public Boolean ifExists(DbConnection data, String kelime, SQLiteDatabase db) {
    Cursor c = db.rawQuery("SELECT * FROM Mylist WHERE Name = ?", new String[] {kelime});
    int rows = c.getCount();
    c.close();
    return rows > 0;
}

我简化了大部分代码，因为您不需要循环。
我也没有看到哪里需要参数DbConnection。