有关解决方案的帮助，我在SQL表中添加了新列。但是在日志中显示以下错误：
SQLiteLog: (1) table tbl_order has no column named Menu_quantity
这是我的DBHelper，在其中添加了：private final String MENU_QUANTITY = "Menu_quantity";
public class DBHelper extends SQLiteOpenHelper{
String DB_PATH;
private final static String DB_NAME = "db_order";
public final static int DB_VERSION = 2;
public static SQLiteDatabase db;
private final Context context;
private final String TABLE_NAME = "tbl_order";
private final String ID = "id";
private final String MENU_NAME = "Menu_name";
private final String QUANTITY = "Quantity";
private final String TOTAL_PRICE = "Total_price";
private final String MENU_QUANTITY = "Menu_quantity";
public DBHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
this.context = context;
DB_PATH = Constant.DBPath;
DB_PATH = Constant2.DBPath;
DB_PATH = Constant3.DBPath;
}
public void createDataBase() throws IOException{
boolean dbExist = checkDataBase();
//SQLiteDatabase db_Read = null;
if(dbExist){
//do nothing - database already exist
}else{
this.getReadableDatabase();
//db_Read = this.getReadableDatabase();
// db_Read.close();
try {
copyDataBase();
} catch (IOException e) {
e.printStackTrace();
// throw new Error("Error copying database");
}
}
}
private boolean checkDataBase(){
File dbFile = new File(DB_PATH + DB_NAME);
return dbFile.exists();
}
private void copyDataBase() throws IOException{
InputStream myInput = context.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException{
String myPath = DB_PATH + DB_NAME;
db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
@Override
public void close() {
db.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion > oldVersion) {
db.execSQL("ALTER TABLE tbl_order ADD COLUMN Menu_quantity INTEGER DEFAULT 0");
}
}
/** This code is used to retrieve all data from the database. */
public ArrayList<ArrayList<Object>> getAllData(){
ArrayList<ArrayList<Object>> dataArrays = new ArrayList<ArrayList<Object>>();
Cursor cursor = null;
try{
cursor = db.query(
TABLE_NAME,
new String[]{ID, MENU_NAME, QUANTITY, TOTAL_PRICE, MENU_QUANTITY},
null,null, null, null, null, null);
cursor.moveToFirst();
if (!cursor.isAfterLast()){
do{
ArrayList<Object> dataList = new ArrayList<Object>();
dataList.add(cursor.getLong(0));
dataList.add(cursor.getString(1));
dataList.add(cursor.getString(2));
dataList.add(cursor.getString(3));
dataList.add(cursor.getString(4));
dataArrays.add(dataList);
}
while (cursor.moveToNext());
}
cursor.close();
}catch (SQLException e){
Log.e("DB Error", e.toString());
e.printStackTrace();
}
return dataArrays;
}
/** This code is used to retrieve all data from the database. */
public boolean isDataExist(long id){
boolean exist = false;
Cursor cursor = null;
try{
cursor = db.query(
TABLE_NAME,
new String[]{ID},
ID +"="+id,
null, null, null, null, null);
if(cursor.getCount() > 0){
exist = true;
}
cursor.close();
}catch (SQLException e){
Log.e("DB Error", e.toString());
e.printStackTrace();
}
return exist;
}
/** This code is used to retrieve all data from the database. */
public boolean isPreviousDataExist(){
boolean exist = false;
Cursor cursor = null;
try{
cursor = db.query(
TABLE_NAME,
new String[]{ID},
null,null, null, null, null);
if(cursor.getCount() > 0){
exist = true;
}
cursor.close();
}catch (SQLException e){
Log.e("DB Error", e.toString());
e.printStackTrace();
}
return exist;
}
public void addData(long id, String menu_name, int quantity, double total_price, int menu_quantity){
// this is the key holder of the value pair used by the SQLite functions for Android
ContentValues values = new ContentValues();
values.put(ID, id);
values.put(MENU_NAME, menu_name);
values.put(QUANTITY, quantity);
values.put(TOTAL_PRICE, total_price);
values.put(MENU_QUANTITY, menu_quantity);
// ask the database object to insert new data
try{db.insert(TABLE_NAME, null, values);}
catch(Exception e)
{
Log.e("DB ERROR", e.toString());
e.printStackTrace();
}
}
public void deleteData(long id){
// ask the database manager to delete the row of the given identifier
try {db.delete(TABLE_NAME, ID + "=" + id, null);}
catch (Exception e)
{
Log.e("DB ERROR", e.toString());
e.printStackTrace();
}
}
public void deleteAllData(){
// ask the database manager to delete the row of the given identifier
try {db.delete(TABLE_NAME, null, null);}
catch (Exception e)
{
Log.e("DB ERROR", e.toString());
e.printStackTrace();
}
}
public void updateData(long id, int quantity, double total_price){
// this is the key holder of the value pair used by the SQLite functions for Android
ContentValues values = new ContentValues();
values.put(QUANTITY, quantity);
values.put(TOTAL_PRICE, total_price);
// values.put(MENU_QUANTITY, menu_quantity);
// попросите объект базы данных обновить строку базы данных заданного rowID
try {db.update(TABLE_NAME, values, ID + "=" + id, null);}
catch (Exception e)
{
Log.e("DB Error", e.toString());
e.printStackTrace();
}
}
这是我将变量发送到DBHelper的方式：
// when you click the add button, add the menu to the table of orders in the database
if(!temp.equalsIgnoreCase("")){
quantity = Integer.parseInt(temp);
if(dbhelper.isDataExist(Menu_ID)){
dbhelper.updateData(Menu_ID, quantity, (Menu_price*quantity));
}else{
dbhelper.addData( Menu_ID, Menu_name, quantity, (Menu_price*quantity), Menu_quantity);
}
}else{
dialog.cancel();
}
}
});