In the code block, where the transferred values ​​of values ​​are checked for the presence of inserted data for certain columns, if there is no data, why put an empty value? If the columns in the database have a default value, are these lines still necessary?

@Override public Uri insert(Uri uri, ContentValues initialValues) { if ( sUriMatcher.match(uri) != STUDENTS && sUriMatcher.match(uri) != CLASSES ) { throw new IllegalArgumentException("Unknown URI " + uri); } SQLiteDatabase db = dbHelper.getWritableDatabase(); ContentValues values; if (initialValues != null) { values = new ContentValues(initialValues); } else { values = new ContentValues(); } long rowId = -1; Uri rowUri = Uri.EMPTY; switch (sUriMatcher.match(uri)) { case STUDENTS: if (values.containsKey(ContractClass.Students.COLUMN_NAME_FIRST_NAME) == false) { values.put(ContractClass.Students.COLUMN_NAME_FIRST_NAME, ""); } if (values.containsKey(ContractClass.Students.COLUMN_NAME_SECOND_NAME) == false) { values.put(ContractClass.Students.COLUMN_NAME_SECOND_NAME, ""); } if (values.containsKey(ContractClass.Students.COLUMN_NAME_AVERAGE_SCORE) == false) { values.put(ContractClass.Students.COLUMN_NAME_AVERAGE_SCORE, 0.0); } if (values.containsKey(ContractClass.Students.COLUMN_NAME_FK_CLASS_ID) == false) { values.put(ContractClass.Students.COLUMN_NAME_FK_CLASS_ID, -1); } rowId = db.insert(ContractClass.Students.TABLE_NAME, ContractClass.Students.COLUMN_NAME_FIRST_NAME, values); if (rowId > 0) { rowUri = ContentUris.withAppendedId(ContractClass.Students.CONTENT_ID_URI_BASE, rowId); getContext().getContentResolver().notifyChange(rowUri, null); } break; case CLASSES: if (values.containsKey(ContractClass.Classes.COLUMN_NAME_CLASS_NUMBER) == false) { values.put(ContractClass.Classes.COLUMN_NAME_CLASS_NUMBER, ""); } if (values.containsKey(ContractClass.Classes.COLUMN_NAME_CLASS_LETTER) == false) { values.put(ContractClass.Classes.COLUMN_NAME_CLASS_LETTER, ""); } rowId = db.insert(ContractClass.Classes.TABLE_NAME, ContractClass.Classes.COLUMN_NAME_CLASS_NUMBER, values); if (rowId > 0) { rowUri = ContentUris.withAppendedId(ContractClass.Classes.CONTENT_ID_URI_BASE, rowId); getContext().getContentResolver().notifyChange(rowUri, null); } break; } return rowUri; }

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