Differentiate between Hive internal tables an external tables

Question

Can you elaborate the difference between Hive internal tables and external tables? I understood that it differs in the way it drops the tables down but why do the table schema and table data get deleted in internal tables and why the external tables delete only the schema of the table? Explain to me this in terms of nodes.

Answer 1

Hive comprises of an RDBMS(Relational-Database-Management-Systems) on its Master-Node which is used to keep track of the status of the data table.

consider you create a certain table with a certain schema or meta-data, then this particular schema is stored in the RDBMS. In case, if the table is partitioned, then these partitions are stored into a database and hive is allowed to use these lists of partitions to access the data with having the need to go the original file-system to fetch the data. this data which helps the Hive to fetch data is known as Metadata.

This is why when the internal table is dropped, the data along with its schema(metadata) is also dropped.

And when an external table is dropped, only the metadata is dropped making the Hive to ignore the data present in the table.