如何将多个值从一个表插入到另一表的一列？

Question

我正在创建android应用，并且在一项活动中我需要创建锻炼计划。 从微调器中，我选择练习名称（来自其他表格）。 我可以选择多个练习。 那么哪种方法最好呢？ 我尝试将一些练习添加到ArrayList并将该ArrayList保存到数据库，但是我没有找到一种方法。 而且我需要能够编辑锻炼计划（例如：删除或添加锻炼），所以我认为ArrayList不是解决方案。

我意识到这是多对多的关系（很多锻炼可以在很多锻炼计划中进行），所以我创建了包含锻炼ID和锻炼ID的表格：

   private static final String CREATE_TABLE_TRAININGEXERCISE = 
"CREATE TABLE " + TABLE_TRAININGEXERCISE + "(" + TEXERCISE_ID + 
" INTEGER," + TWORKOUT_ID + " INTEGER," + "FOREIGN KEY (TExerciseID) REFERENCES "
 + TABLE_EXERCISE + " (ExerciseID)," +
 " FOREIGN KEY (TWorkoutID) REFERENCES " + TABLE_WORKOUT + " (WorkoutID))";
}

我希望我的锻炼计划看起来像这样：

• 职称：胸
• 练习：卧推4x8 | 斜卧推3x12 | 飞行3x12 |

那么如何将这3个练习保存到一栏？

Answer 1

这是一个示例，它根据您的架构来完成您所要求的

1. 它通过ArrayList（使用ID的ArrayList）通过映射表（TRAININGEXERCISE）向锻炼中添加了许多练习。
2. 它产生的输出与您想要的（类似于日志）类似，例如示例日志

： -

2019-05-13 13:13:46.736  D/MYDATA: Workout: Chest
        EXERCISES: Bench press,Incline bench press,Flies
2019-05-13 13:13:46.736  D/MYDATA: Workout: Abdomen
        EXERCISES: hump,lug,roll
2019-05-13 13:13:46.736  D/MYDATA: Workout: Everything
        EXERCISES: hump,lug,roll,kneel,Bench press,Incline bench press,Flies,Flip

使用的数据库助手DBHelper.java是：-

public class DBHelper extends SQLiteOpenHelper {

    public static final String DBNAME = "workout";
    public static final int DBVERSION = 1;

    public static final String TABLE_TRAININGEXERCISE = "training_excercise"; //<<<<<<<< OOOPS spelling :)
    public static final String TABLE_WORKOUT = "workout";
    public static final String TABLE_EXERCISE = "exersise"; //<<<<<<< OOOPS spelling :)
    public static final String TWORKOUT_ID = "WorkoutID";
    public static final String TWORKOUT_NAME = "workour_name";

    public static final String TEXERCISE_ID = "ExerciseID";
    public static final String TEXERCISE_NAME = "exercise_name";

    public static final String TTEEXERCISELINK = "TExerciseID"; //<<<<<<<<<< ADDED
    public static final String TTEWORKOUTLINK = "TWorkoutID"; //<<<<<<<<<< ADDED

    // Note as entities are always derived from constants above the spelling mistakes are irrelvant
    // (need a better smellchecker :) )

    //<<<<<<<<<< ENOUGH TO DEMONSTRATE >>>>>>>>>>
    private static final String CREATE_TABLE_WORKOUT =
            "CREATE TABLE " + TABLE_WORKOUT + "(" +
                    TWORKOUT_ID + " INTEGER PRIMARY KEY," +
                    TWORKOUT_NAME + " TEXT" +
                    ")";

    //<<<<<<<<<< ENOUGH TO DEMONSTRATE >>>>>>>>>>
    private static final String CREATE_TABLE_EXERCISE =
            "CREATE TABLE " + TABLE_EXERCISE + "(" +
                    TEXERCISE_ID + " INTEGER PRIMARY KEY," +
                    TEXERCISE_NAME + " TEXT " +
                    ")";

    //<<<<<<<<<<NOTE Uses constants for all entity names >>>>>>>>>> (see new ones above)
    private static final String CREATE_TABLE_TRAININGEXERCISE =
            "CREATE TABLE " + TABLE_TRAININGEXERCISE + "(" +
                    TTEEXERCISELINK + " INTEGER," +
                    TTEWORKOUTLINK + " INTEGER," +

                    "FOREIGN KEY (" + TTEEXERCISELINK + ") " +
                    "REFERENCES " + TABLE_EXERCISE + " (" + TEXERCISE_ID + ")," +

                    " FOREIGN KEY (" + TTEWORKOUTLINK + ") " +
                    "REFERENCES " + TABLE_WORKOUT + " (" + TWORKOUT_ID + "))";

    public DBHelper(Context context) {
        super(context, DBNAME, null, DBVERSION);
    }

    @Override
    public void onConfigure(SQLiteDatabase db) {
        super.onConfigure(db);
        db.setForeignKeyConstraintsEnabled(true); //<<<<<<<<<< MUST HAVE FOR FOREIGN KEYS
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CREATE_TABLE_EXERCISE);
        db.execSQL(CREATE_TABLE_WORKOUT);
        db.execSQL(CREATE_TABLE_TRAININGEXERCISE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    public long addWorkout(String name) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();
        cv.put(TWORKOUT_NAME,name);
        return db.insert(TABLE_WORKOUT,null,cv);
    }

    public long addExecise(String name) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();
        cv.put(TEXERCISE_NAME,name);
        return db.insert(TABLE_EXERCISE,null,cv);
    }

    public long addExcerciseToWorkout(long workoutid, long exerciseid) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cv = new ContentValues();
        cv.put(TTEWORKOUTLINK,workoutid);
        cv.put(TTEEXERCISELINK,exerciseid);
        return db.insert(TABLE_TRAININGEXERCISE,null,cv);
    }

    //<<<<<<<<<< ADD MANY EXERCISES to a WORKOUT via an ArrayList
    public void addManyExcercisesToWorkout(long workoutid,ArrayList<Long> exerciseids) {
        ArrayList<Long> rv = new ArrayList<>();
        SQLiteDatabase db = this.getWritableDatabase();
        db.beginTransaction();
        for (Long l: exerciseids) {
            long thisid = addExcerciseToWorkout(workoutid,l);
        }
        db.setTransactionSuccessful();
        db.endTransaction();
    }

    //<<<<<<<<<< Get all the exercises per workout via the group_concat function >>>>>>>>>>
    public void logAllWorkoutsWithExcercises() {
        SQLiteDatabase db = this.getWritableDatabase();
        //<<<<<<<<<< column name aliases (not required but desireable as they can be quite cumbersome) >>>>>>>>>>
        String workoutname_column_alias = "thisworkoutname";
        String concantenated_exercises_alias = "all_exercises";

        String tables = TABLE_WORKOUT +
                " JOIN " + TABLE_TRAININGEXERCISE + " ON " + TABLE_WORKOUT + "." + TWORKOUT_ID + "="  + TTEWORKOUTLINK +
                " JOIN " + TABLE_EXERCISE + " ON " + TTEEXERCISELINK +  "=" + TABLE_EXERCISE + "." + TEXERCISE_ID;
        String[] columns = new String[]{
                TABLE_WORKOUT + "." + TWORKOUT_NAME + " AS " + workoutname_column_alias,
                "'\n\tEXERCISES: '||group_concat(" +
                        TABLE_EXERCISE + "." + TEXERCISE_NAME +
                        ") AS " + concantenated_exercises_alias
        };
        String groupby = TABLE_WORKOUT + "." + TWORKOUT_ID;
        // Query resolves to :-
        /*
            SELECT 
                workout.workour_name AS thisworkoutname, 
                'EXERCISES: '||group_concat(exersise.exercise_name) AS all_exercises 
            FROM workout 
                JOIN training_excercise ON  workout.WorkoutID=TWorkoutID 
                JOIN exersise ON TExerciseID=exersise.ExerciseID 
                GROUP BY workout.WorkoutID
        */
        Cursor csr = db.query(tables,columns,null,null,groupby,null,null);
        while (csr.moveToNext()) {
            Log.d(
                    "MYDATA",
                    "Workout: " +
                            csr.getString(csr.getColumnIndex(workoutname_column_alias)) +
                            csr.getString(csr.getColumnIndex(concantenated_exercises_alias))
            );
        }
        csr.close();
    }
}

测试是通过以下活动进行的：

public class MainActivity extends AppCompatActivity {
    String[] allexcercises = new String[]{"hump", "lug", "roll", "kneel", "Bench press", "Incline bench press", "Flies","Flip"};
    // Note assume that hump is id 1, lug id 2 etc
    String[] allworkouts = new String[]{"Chest","Abdomen","Everything"};

    ArrayList<Long> chest_excercises = new ArrayList<>();
    ArrayList<Long> abdomen_excercises = new ArrayList<>();
    ArrayList<Long> everything_excercises = new ArrayList<>();

    DBHelper mDBHlpr;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDBHlpr = new DBHelper(this);
        addSomeData(); //<<<<<<<<<< Adds the testing data (only designed to run once)
        mDBHlpr.logAllWorkoutsWithExcercises(); //<<<<<<<<<< Output workouts with excercises
    }

    private void addSomeData() {
        // Excercises
        mDBHlpr.getWritableDatabase().beginTransaction();
        for (String excercise: allexcercises) {
            mDBHlpr.addExecise(excercise);
        }
        for (String workout: allworkouts) {
            mDBHlpr.addWorkout(workout);
        }
        mDBHlpr.getWritableDatabase().setTransactionSuccessful();
        mDBHlpr.getWritableDatabase().endTransaction();

        // Build ArrayLists as if from multiple spinner selections
        chest_excercises.add(new Long(5));
        chest_excercises.add(new Long(6));
        chest_excercises.add(new Long(7));

        abdomen_excercises.add(new Long(1));
        abdomen_excercises.add(new Long(2));
        abdomen_excercises.add(new Long(3));

        // Add all excercises to the everything workout ArrayList
        for(int l=1; l <= allexcercises.length; l++) {
            everything_excercises.add(new Long((long) l));
        }
        // Add multiple exercises per workout
        mDBHlpr.addManyExcercisesToWorkout(1,chest_excercises);
        mDBHlpr.addManyExcercisesToWorkout(2,abdomen_excercises);
        mDBHlpr.addManyExcercisesToWorkout(3,everything_excercises);

    }
}

Answer 2

您无需将所有练习名称都推到一栏中（这与您创建的表方案相矛盾，如果这样做，将很难进行操作），您需要将每个练习插入到TABLE_TRAININGEXERCISE中自己的记录中，并将其链接到一次锻炼，下一步是将ArrayList添加到锻炼模型中，通过使用添加使用锻炼ID从TABLE_TRAININGEXERCISE获取所有记录的方法，您将在其中填充与该锻炼ID相关的所有锻炼的列表。

这样，您就可以更轻松地进行锻炼练习（插入，更新或删除），并且可以通过打印锻炼名称并遍历其锻炼并用逗号将其加入来实现所需的输出。