Using complex data types

In addition to primitive data types, Hive also supports a few complex data types: Struct, MAP, and Array. Complex data types are also known as collection data types. Most relational databases don't support such data types.

Complex data types can be built from primitive data types:

• STRUCT: The struct data type in Hive is analogous to the STRUCT in C programming language. It is a record type that holds a set of named fields that can be of any primitive data types. Fields in the STRUCT type are accessed using the DOT (.) notation.

  Syntax: STRUCT<col_name : data_type [COMMENT col_comment], ...>

  For example, if a column address is of the type STRUCT {city STRING; state STRING}, then the city field can be referenced using address.city.

• MAP: The map data type contains key-value pairs. In Map, elements are accessed using the keys. For example, if a column name is of type Map: 'firstname' -> 'john' and 'lastname' -> 'roy', then the last name can be accessed using the...