Question

我有一个目前正常的应用程序。它基本上是一个练习应用程序，其中所有用户的练习条目都保存在表格中。问题是，此应用程序目前只适用于一个用户，我想让它适用于多个用户，但为此，我需要为每个用户提供一个单独的练习数据库表。我怎么能这样做？

我不知道它是否相关，但以下是我当前数据库代码的重要部分：

private static final String USER_TABLE_CREATE =
    "create table if not exists UserProfile ( id integer primary key autoincrement,"
    + "age VARCHAR not null, weight VARCHAR not null, height VARCHAR not null, sex VARCHAR not null);";

private static final String RUNNER_TABLE_CREATE =        
        "create table if not exists RunnerHistoryTable ( id integer primary key autoincrement,"
        + "recommendation VARCHAR , activitydate VARCHAR , activity_distance VARCHAR , activity_time VARCHAR, activity_velocity VARCHAR, monitor VARCHAR, calories VARCHAR);";
private static final String WALKER_TABLE_CREATE =        
        "create table if not exists WalkerHistoryTable ( id integer primary key autoincrement,"
        + "recommendation VARCHAR , activitydate VARCHAR , activity_distance VARCHAR , activity_time VARCHAR, activity_velocity VARCHAR, monitor VARCHAR, calories VARCHAR);";
private static final String WEIGHT_LOSS_TABLE_CREATE =        
        "create table if not exists WeightLossHistoryTable (id integer primary key autoincrement, "
        + " recommendation VARCHAR , activitydate VARCHAR, activity_distance VARCHAR , activity_time VARCHAR, activity_velocity VARCHAR, monitor VARCHAR, calories VARCHAR);";

private final Context context;    

private DatabaseHelper DBHelper;
private SQLiteDatabase db;

public DatabaseAdapter(Context ctx) 
{
    this.context = ctx;
    DBHelper = new DatabaseHelper(context);
}

private static class DatabaseHelper extends SQLiteOpenHelper 
{
    DatabaseHelper(Context context) 
    {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) 
    {
        try {
            db.execSQL(USER_TABLE_CREATE);
            db.execSQL(RUNNER_TABLE_CREATE);
            db.execSQL(WALKER_TABLE_CREATE);
            db.execSQL(WEIGHT_LOSS_TABLE_CREATE);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
 }

//---insert a record into the database---

public long insertUser(String age, String weight, String height,String sex){
    ContentValues initialValues = new ContentValues();

    initialValues.put(AGE,age);
    initialValues.put(WEIGHT,weight);
    initialValues.put(HEIGHT,height);
    initialValues.put(SEX, sex);

    return db.insert(USER_PROFILE_TABLE, null, initialValues);
}

public long insertActivity(String tableName, String recommendation, String activityDate, String activityDistance, String activityTime, String activityVelocity, String monitor, String calories){
    ContentValues initialValues = new ContentValues();

    initialValues.put(RECOMMENDATION,recommendation);
    initialValues.put(ACTIVITY_DATE,activityDate);
    initialValues.put(ACTIVITY_DISTANCE,activityDistance);
    initialValues.put(ACTIVITY_TIME, activityTime);
    initialValues.put(ACTIVITY_VELOCITY, activityVelocity);
    initialValues.put(MONITOR, monitor);
    initialValues.put(CALORIES, calories);

    return db.insert(tableName, null, initialValues);   
}

Answer 1

您的数据库应该只有两个表，一个用于存储用户，另一个用于存储活动（将activitytype列添加到“活动”表）。然后，您需要使用外键约束将用户绑定到活动。

private static final String USER_TABLE_CREATE =
    "create table if not exists Users ( id integer primary key autoincrement,"
    + "age text not null, weight text not null, height text not null, sex text not null);";

private static final String ACTIVITIES_TABLE_CREATE =        
    "create table if not exists Activities ( id integer primary key autoincrement,"
    + "userid int, activitytype text, recommendation text, activitydate text, activity_distance text,"
    + "activity_time text, activity_velocity text, monitor text, calories text,"
    + "FOREIGN KEY(userid) REFERENCES Users(id));";

在Android中使用同一数据库的多个表

1 个答案: