Schema – structure of data

A schema is the description of the structure of your data and can be either implicit or explicit. There are two main ways to convert existing RDDs into datasets as the DataFrames are internally based on the RDD; they are as follows:

• Using reflection to infer the schema of the RDD
• Through a programmatic interface with the help of which you can take an existing RDD and render a schema to convert the RDD into a dataset with schema

Implicit schema

Let's look at an example of loading a comma-separated values (CSV) file into a DataFrame. Whenever a text file contains a header, the read API can infer the schema by reading the header line. We also have the option to specify the separator...