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我有List一些要插入数据库的对象。我在 foreach 循环中创建了插入插入,但它仍然以异常约束失败结束。在我的表中,我创建了 column '_id' INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL。我的插入方法看起来像

    public void insertData(List<Item> list) {
        dbAdapter = DBAdapter.getDBAdapterInstance(getActivity());
        dbAdapter.openDataBase();
        for (Itemm item : list) {
            ContentValues values = new ContentValues();
            values.put("item_id", item.getItemId());
            values.put("item_category", item.getItemCategory());
            values.put("order_number", item.getOrderNumber());
            dbAdapter.insertRecordsInDB("order_list", null, values);
          }
          dbAdapter.close();
}

这是 DBAdapter 类:

public class DBAdapter extends SQLiteOpenHelper {

    private static String DB_PATH = "/data/data/<my_package>/databases/";
    private static String DB_NAME = "mydatabase.db";
    private static final int DB_VERSION = 1;

    private SQLiteDatabase myDataBase;
    private final Context myContext;

    private static DBAdapter myDBAdapter;

    /**
     * Constructor Takes and keeps a reference of the passed context in order to
     * access to the application assets and resources.
     * 
     * @param context
     */
    private DBAdapter(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
        this.myContext = context;
    }

    /**
     * getting Instance
     * 
     * @param context
     * @return DBAdapter
     */
    public static synchronized DBAdapter getDBAdapterInstance(Context context) {
        if (myDBAdapter == null) {
            myDBAdapter = new DBAdapter(context);
        }
        return myDBAdapter;
    }

    /**
     * Creates an empty database on the system and rewrites it with your own
     * database.
     **/
    public void createDataBase() throws IOException {
        boolean dbExist = checkDataBase();
        if (dbExist) {
            // do nothing - database already exist
        } else {
            // By calling following method
            // 1) an empty database will be created into
            // the default system path of your application
            // 2) than we overwrite that database with our database.
            this.getReadableDatabase();
            try {
                copyDataBase();
            } catch (IOException e) {
                throw new Error("Error copying database");
            }
        }
    }

    /**
     * Check if the database already exist to avoid re-copying the file each
     * time you open the application.
     * 
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase() {
        //SQLiteDatabase checkdb = null;
        boolean checkdb = false;
        try{
            String myPath = DB_PATH + DB_NAME;
            File dbfile = new File(myPath);
            //checkdb = SQLiteDatabase.openDatabase(myPath,null,SQLiteDatabase.OPEN_READWRITE);
            checkdb = dbfile.exists();
        }
        catch(SQLiteException e){
            System.out.println("Database doesn't exist");
        }

        return checkdb;
    }

    /**
     * Copies your database from your local assets-folder to the just created
     * empty database in the system folder, from where it can be accessed and
     * handled. This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException {
        // Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(DB_NAME);
        // Path to the just created empty db
        String outFileName = DB_PATH + DB_NAME;
        // Open the empty db as the output stream
        OutputStream myOutput = new FileOutputStream(outFileName);
        // transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer)) > 0) {
            myOutput.write(buffer, 0, length);
        }
        // Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();
    }

    /**
     * Open the database
     * 
     * @throws SQLException
     */
    public void openDataBase() throws SQLException {
        String myPath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null,
                SQLiteDatabase.OPEN_READWRITE);
        if (!myDataBase.isReadOnly()) {
            myDataBase.execSQL("PRAGMA foreign_keys=ON;");
        }
    }

    /**
     * Close the database if exist
     */
    @Override
    public synchronized void close() {
        if (myDataBase != null)
            myDataBase.close();
        super.close();
    }

    /**
     * Call on creating data base for example for creating tables at run time
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
    }

    /**
     * can used for drop tables then call onCreate(db) function to create tables
     * again - upgrade
     */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    }

    // ----------------------- CRUD Functions ------------------------------

    /**
     * This function used to select the records from DB.
     * 
     * @param tableName
     * @param tableColumns
     * @param whereClase
     * @param whereArgs
     * @param groupBy
     * @param having
     * @param orderBy
     * @return A Cursor object, which is positioned before the first entry.
     */
    public Cursor selectRecordsFromDB(String tableName, String[] tableColumns,
            String whereClase, String whereArgs[], String groupBy,
            String having, String orderBy) {
        return myDataBase.query(tableName, tableColumns, whereClase, whereArgs,
                groupBy, having, orderBy);
    }

    /**
     * select records from db and return in list
     * 
     * @param tableName
     * @param tableColumns
     * @param whereClase
     * @param whereArgs
     * @param groupBy
     * @param having
     * @param orderBy
     * @return ArrayList<ArrayList<String>>
     */
    public ArrayList<ArrayList<String>> selectRecordsFromDBList(
            String tableName, String[] tableColumns, String whereClase,
            String whereArgs[], String groupBy, String having, String orderBy) {
        ArrayList<ArrayList<String>> retList = new ArrayList<ArrayList<String>>();
        ArrayList<String> list = new ArrayList<String>();
        Cursor cursor = myDataBase.query(tableName, tableColumns, whereClase,
                whereArgs, groupBy, having, orderBy);
        if (cursor.moveToFirst()) {
            do {
                list = new ArrayList<String>();
                for (int i = 0; i < cursor.getColumnCount(); i++) {
                    list.add(cursor.getString(i));
                }
                retList.add(list);
            } while (cursor.moveToNext());
        }
        if (cursor != null && !cursor.isClosed()) {
            cursor.close();
        }
        return retList;

    }

    /**
     * This function used to insert the Record in DB.
     * 
     * @param tableName
     * @param nullColumnHack
     * @param initialValues
     * @return the row ID of the newly inserted row, or -1 if an error occurred
     */
    public long insertRecordsInDB(String tableName, String nullColumnHack,
            ContentValues initialValues) {
        return myDataBase.insert(tableName, nullColumnHack, initialValues);
    }

    /**
     * This function used to update the Record in DB.
     * 
     * @param tableName
     * @param initialValues
     * @param whereClause
     * @param whereArgs
     * @return true / false on updating one or more records
     */
    public boolean updateRecordInDB(String tableName,
            ContentValues initialValues, String whereClause, String whereArgs[]) {
        return myDataBase.update(tableName, initialValues, whereClause,
                whereArgs) > 0;
    }

    /**
     * This function used to update the Record in DB.
     * 
     * @param tableName
     * @param initialValues
     * @param whereClause
     * @param whereArgs
     * @return 0 in case of failure otherwise return no of row(s) are updated
     */
    public int updateRecordsInDB(String tableName, ContentValues initialValues,
            String whereClause, String whereArgs[]) {
        return myDataBase.update(tableName, initialValues, whereClause,
                whereArgs);
    }

    /**
     * This function used to delete the Record in DB.
     * 
     * @param tableName
     * @param whereClause
     * @param whereArgs
     * @return 0 in case of failure otherwise return no of row(s) are deleted.
     */
    public int deleteRecordInDB(String tableName, String whereClause,
            String[] whereArgs) {
        return myDataBase.delete(tableName, whereClause, whereArgs);
    }

    // --------------------- Select Raw Query Functions ---------------------

    /**
     * apply raw Query
     * 
     * @param query
     * @param selectionArgs
     * @return Cursor
     */
    public Cursor selectRecordsFromDB(String query, String[] selectionArgs) {
        return myDataBase.rawQuery(query, selectionArgs);
    }

    /**
     * apply raw query and return result in list
     * 
     * @param query
     * @param selectionArgs
     * @return ArrayList<ArrayList<String>>
     */
    public ArrayList<ArrayList<String>> selectRecordsFromDBList(String query,
            String[] selectionArgs) {
        ArrayList<ArrayList<String>> retList = new ArrayList<ArrayList<String>>();
        ArrayList<String> list = new ArrayList<String>();
        Cursor cursor = myDataBase.rawQuery(query, selectionArgs);
        if (cursor.moveToFirst()) {
            do {
                list = new ArrayList<String>();
                for (int i = 0; i < cursor.getColumnCount(); i++) {
                    list.add(cursor.getString(i));
                }
                retList.add(list);
            } while (cursor.moveToNext());
        }
        if (cursor != null && !cursor.isClosed()) {
            cursor.close();
        }
        return retList;
    }

}

我不知道我做错了什么。如何将列表中的数据插入数据库?感谢您的每一次帮助。谢谢你。

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