The data type representing Maps. A MapType object comprises two fields,
DataType keyType
,
DataType valueType
, and
boolean valueContainsNull
.
The field of
keyType
is used to specify the type of keys in the map.
The field of
valueType
is used to specify the type of values in the map.
The field of
valueContainsNull
is used to specify if map values have
null
values.
For values of a MapType column, keys are not allowed to have
null
values.
To create a
MapType
,
DataType.createMapType(DataType, DataType)
or
DataType.createMapType(DataType, DataType, boolean)
should be used.