I am new to databricks platform.

1. what is the best way to keep data persistent so that once I restart the cluster I don't need to run all the codes again?So that I can simply continue developing my notebook with the cached data.
2. I have created many dataframes and I want to save them as Delta table using the code

dataFrame.to_delta('/dbfs/Projects/', index_col='index')

1. then I list the table using the command I see a table with two columns: path, and name. The path column contains the path starting from dbfs:/dbfs/Projects/part-00000-xxxx-snappy.parquet. The name column has only the filename part. How will I later query those two tables if the dataframe name is not saved with the filename. Do I have to query by the extremely long filename.?