Apache Hive Schema On Read.
Why apache hive called schema on read not schema on write?
In relation database systems, let’s say we perform any insert or update operations in this case database has full control over the storage and database can enforce the schema as data is written, this statement in relation databases called schema on write.
However, hive has no control over the storage (Ex. HDFS), there are many possible ways in Hadoop to damage the hive warehouse data and that’s why hive can only apply query on read which called schema on read.