Package org.apache.drill.exec.record.metadata

Provides a fluent schema builder.

See: Description

Interface Summary

Interface	Description
ColumnMetadata	Metadata description of a column including names, types and structure information.
Propertied	Interface for an object that defines properties.
TupleMetadata	Metadata description of the schema of a row or a map.
VariantMetadata	Describes the contents of a list or union field.

Class Summary

Class	Description
AbstractColumnMetadata	Abstract definition of column metadata.
AbstractMapColumnMetadata	Describes a base column type for map, dict, repeated map and repeated dict.
AbstractPropertied	Base class for an object with properties.
ColumnBuilder	Build a column schema (AKA "materialized field") based on name and a variety of schema options.
DictBuilder	Internal structure for building a dict.
DictColumnMetadata
DynamicColumn	A dynamic column has a name but not a type.
MapBuilder	Internal structure for building a map.
MapColumnMetadata	Describes a map and repeated map.
MetadataUtils	A collection of utility methods for working with column and tuple metadata.
PrimitiveColumnMetadata	Primitive (non-map) column.
PropertyAccessor	Utilities to get/set typed values within a propertied object
RepeatedListBuilder	Builder for a repeated list.
RepeatedListColumnMetadata
SchemaBuilder	Builder of a row set schema expressed as a list of materialized fields.
TupleBuilder	Internal tuple builder shared by the schema and map builders.
TupleNameSpace<T>	Implementation of a tuple name space.
TupleSchema	Defines the schema of a tuple: either the top-level row or a nested "map" (really structure).
UnionBuilder	Builds unions or (non-repeated) lists (which implicitly contain unions.) Class can be created with and without parent container.
VariantColumnMetadata
VariantSchema

Enum Summary

Enum	Description
ColumnMetadata.StructureType	Rough characterization of Drill types into metadata categories.

Package org.apache.drill.exec.record.metadata Description

Provides a fluent schema builder. Handles all forms of Drill schemas, with emphasis on ease of use for the typical cases (flat schema or nested maps.) Enables construction of unions, union lists (AKA "list vector") repeated lists and combinations of the above structures.

SchemaBuilder

Drill normally writes data to vectors, then "discovers" the row set schema based on the data written. It is usually far easier to simply declare a schema, then read and write data according to that schema. The schema builder provides a simple, fluent tool to create a row set schema. That schema then drives the row set readers and writers, the row set printer and the row set comparison.