I am trying to create a database and fill it with values gotten from an excel sheet.
new_db = pd.DataFrame()
workbook = pd.ExcelFile(filename)
df = workbook.parse('Sheet1')
You need to reassign the df after appending to it, as @ayhan pointed out in the comments:
new_db = new_db.append(df)
From the Panda's Documentation for append, it returns an appended dataframe, which means you need to assign it to a variable.