ORMLite update of the database

Question

I\'m actually developing an app which is using ORMLite library (which is wonderful btw) but I\'m a beginner using it.

I have a question about the update of the datab

Answer 1

I don't like to drop database at every upgrade, or write an update code after I add each field, so ...

I'm trying to do it like this:

@Override
public void onUpgrade(SQLiteDatabase database, ConnectionSource connectionSource, int oldVersion, int newVersion) {
    ArrayList tableNames = getTableNames(database);
    for (Class clazz : daoClasses) {
        try {
            Annotation annotation = clazz.getAnnotation(DatabaseTable.class);
            if (annotation != null && annotation instanceof DatabaseTable) {
                String tableName = ((DatabaseTable) annotation).tableName();
                if (tableName.isEmpty()) {
                    tableName = clazz.getSimpleName().substring(0, 1).toLowerCase() + clazz.getSimpleName().substring(1);
                }
                if(!tableNames.contains(tableName)){
                    TableUtils.createTable(connectionSource, clazz);
                } else {
                    addColumns(database, tableName, clazz);
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

private ArrayList getTableNames(SQLiteDatabase database){
    ArrayList tableNames = new ArrayList<>();
    Cursor cursor = database.rawQuery("SELECT name FROM sqlite_master WHERE type='table'", null);
    if (cursor.moveToFirst()) {
        while ( !cursor.isAfterLast() ) {
            tableNames.add(cursor.getString(0));
            cursor.moveToNext();
        }
    }
    cursor.close();
    return tableNames;
}

private void addColumns(SQLiteDatabase database, String tableName, Class clazz){
    Cursor mCursor = database.rawQuery("SELECT * FROM " + tableName + " LIMIT 0", null);
    for (Field field : clazz.getDeclaredFields()) {
        try {
            DatabaseField annotationField = field.getAnnotation(DatabaseField.class);
            if (annotationField != null && !annotationField.foreign()){
                String columnName = field.getName();
                boolean hasColumn = mCursor.getColumnIndex(columnName) != -1;
                if (!hasColumn) {
                    String columnType = field.getType().getSimpleName();
                    if(columnType.equals(String.class.getSimpleName())){
                        columnType = "TEXT";
                    } else {
                        columnType = columnType.toUpperCase();
                    }
                    database.execSQL(MessageFormat.format("ALTER TABLE `{0}` ADD COLUMN {1} {2};", tableName, columnName, columnType));
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    mCursor.close();
}

I hope this code can be better.

Here, i don't delete old tables and columns that were removed from dao's, and I don't create foreign fields (I'm not sure if i need it).