Android。 SQLite數據庫

Question

我有從ID_COLUMN獲取ID在DEPARTMENT_TABLE中的問題。 我想獲得這個ID並將其插入第二個表 - STUDENT_TABLE。

我有兩個表的數據庫。 ONe表適用於學生，且爲空 - 用戶將數據插入表中。第二個是部門，這裏有兩個部門。

如果用戶選擇ID = 2的部門，則必須將此ID插入到DEPARTMENT_ID列中的學生表中。

DatabaseHandler.class 

public class DatabaseHandler extends SQLiteOpenHelper { 

private static final int DATABASE_VERSION = 2; 
private static final String TAG = "DatabaseHandler"; 
private static final String DATABASE_NAME = "studencibazadb.db"; 

private static final String ID_COLUMN = "id"; 

// pola tabeli "wydzial" 
public static final String TABLE_DEPARTMENTS = "departments", 
     KEY_DEPARTMENT =  "wydzial", 
     KEY_SPECIALIZATION = "kierunek"; 
// pola tabeli "students" 
public static final String TABLE_STUDENTS = "students", 
     KEY_FIRSTNAME =   "imie", 
     KEY_SURNAME =   "nazwisko", 
     KEY_INDEKS =   "indeks", 
     KEY_EMAIL =    "email", 
     KEY_NUMER =    "numer", 
     STUDENT_DEPARTMENT_ID = "dept_id"; 

public DatabaseHandler(Context context) { 
    super(context, DATABASE_NAME, null, DATABASE_VERSION); 
} 

@Override 
public void onCreate(SQLiteDatabase db) { 

    db.execSQL("CREATE TABLE " + TABLE_DEPARTMENTS + "(" + ID_COLUMN + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_DEPARTMENT + " TEXT NOT NULL," + KEY_SPECIALIZATION + " TEXT NOT NULL)"); 
    db.execSQL("CREATE TABLE " + TABLE_STUDENTS + "(" + ID_COLUMN + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_FIRSTNAME + " TEXT NOT NULL," + KEY_SURNAME + " TEXT NOT NULL," + KEY_INDEKS + " INTEGER NOT NULL," + KEY_EMAIL + " TEXT NOT NULL," + KEY_NUMER + " TEXT NOT NULL," + STUDENT_DEPARTMENT_ID + " INT)"); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_DEPARTMENTS); 
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_STUDENTS); 
    onCreate(db); 
} 

public ArrayList<String> getAllDepartments() { 
    ArrayList<String> list = new ArrayList<String>(); 
    SQLiteDatabase db = this.getReadableDatabase(); 
    db.beginTransaction(); 
    try{ 
     String selectQuery = "SELECT * FROM " + TABLE_DEPARTMENTS; 
     Cursor cursor = db.rawQuery(selectQuery, null); 

     if(cursor.getCount() > 0){ 
      while(cursor.moveToNext()){ 
       String depname = cursor.getString(cursor.getColumnIndex("wydzial")); 
       //String depId = cursor.getString(cursor.getColumnIndex("id")); 
       list.add(depname); 
       //list.add(depId); 
      } 
     } 
     db.setTransactionSuccessful(); 
    }catch(SQLiteException e){ 
     e.printStackTrace(); 
    } 
    finally{ 
     db.endTransaction(); 
     db.close(); 
    } 
    return list; 
} 

public Cursor getAllData(){ 
    SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor cursor = db.rawQuery("SELECT * FROM " + TABLE_STUDENTS, null); 
    return cursor; 
} 

}

AddActivity.class 

public class AddActivity extends AppCompatActivity implements OnClickListener { 

private DatabaseHandler dbCreate; 
EditText etImie, etNazwisko, etIndeks, etEmail, etTelefon, etShow; 
Button btnSave, btnDisplay; 
Spinner spSpinner; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_add); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 
    getSupportActionBar().setDisplayHomeAsUpEnabled(true); 

    etImie = (EditText)  findViewById(R.id.etImie); 
    etNazwisko = (EditText) findViewById(R.id.etNazwisko); 
    etIndeks = (EditText) findViewById(R.id.etIndeks); 
    etEmail = (EditText) findViewById(R.id.etEmail); 
    etTelefon = (EditText) findViewById(R.id.etTelefon); 
    etShow = (EditText)  findViewById(R.id.etShow); 
    spSpinner = (Spinner) findViewById(R.id.spSpinner); 

    btnSave = (Button)  findViewById(R.id.btnSave); 
    btnSave.setOnClickListener(this); 
    btnDisplay = (Button) findViewById(R.id.btnDisplay); 
    btnDisplay.setOnClickListener(this); 

    dbCreate = new DatabaseHandler(this.getApplicationContext()); 

    ArrayList<String> list = dbCreate.getAllDepartments(); 
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item,list); 
    spSpinner.setAdapter(adapter); 
} 

public boolean onCreateOptionsMenu(Menu menu) { 
    getMenuInflater().inflate(R.menu.menu_baza_stud, menu); 
    return true; 
} 

private void insertInStudentTable(String imie, String nazwisko, int indeks, String email, String telefon) { 
    SQLiteDatabase db = dbCreate.getWritableDatabase(); 

    // ContentValues data_2 = new ContentValues(); 

    //long idOfDepart = db.insertOrThrow("departments", null, data_2); 

    ContentValues data = new ContentValues(); 

    data.put("imie",  imie); 
    data.put("nazwisko", nazwisko); 
    data.put("indeks",  indeks); 
    data.put("email",  email); 
    data.put("numer",  telefon); 
    data.put("dept_id",  idOfDepart); 

    db.insertOrThrow("students", null, data); 
} 

public void onClick(View v) { 
    if(v.getId() == R.id.btnSave) { 
     try { 
      String imie =  etImie.getText().toString(); 
      String nazwisko = etNazwisko.getText().toString(); 
      String sIndex =  etIndeks.getText().toString(); 
      int indeks =  Integer.parseInt(sIndex); 
      String email =  etEmail.getText().toString(); 
      String telefon = etTelefon.getText().toString(); 

      if(imie.length() == 0 || nazwisko.length() == 0 || sIndex.length() == 0 || email.length() == 0 || telefon.length() == 0){ 
       Toast.makeText(getApplicationContext(),"Fill data.", Toast.LENGTH_SHORT).show(); 
      }else{ 
       insertInStudentTable(imie, nazwisko, indeks, email, telefon); 
       Toast.makeText(getApplicationContext(), "Student has been created: " + imie + " " + nazwisko + " .", Toast.LENGTH_SHORT).show(); 
      } 
     } catch (SQLiteException e) { 
      System.err.println(e.toString()); 
     } finally { 
      dbCreate.close(); 
     } 
    } 

} 

}

Answer 1

在機器人的查詢檢索，以便將信息從左到右（0至N）的光標。運行您的查詢並驗證您要使用的列的位置。