org.apache.drill.exec.physical.impl.scan.v3.schema

Enum DynamicSchemaFilter.NewColumnsMode

java.lang.Object

java.lang.Enum<DynamicSchemaFilter.NewColumnsMode>

org.apache.drill.exec.physical.impl.scan.v3.schema.DynamicSchemaFilter.NewColumnsMode

All Implemented Interfaces:

Serializable, Comparable<DynamicSchemaFilter.NewColumnsMode>

Enclosing class:

DynamicSchemaFilter

public static enum DynamicSchemaFilter.NewColumnsMode
extends Enum<DynamicSchemaFilter.NewColumnsMode>

Describes how to handle candidate columns not currently in the scan schema, which turns out to be a surprisingly complex question. At the top level, we add columns only if the query contains a wildcard. But, within maps, there are additional constraints: we can add new members to a map even if the query itself does not contain a wildcard.

Enum Constant Summary

Enum Constants

Enum Constant and Description
ALL New columns are allowed at this level and below.
CHILD_ONLY New columns cannot be added at this level, but can be added in maps below this level.
NONE No new columns are allowed at this level or in maps below this level.

Method Summary

Modifier and Type	Method and Description
static DynamicSchemaFilter.NewColumnsMode	valueOf(String name) Returns the enum constant of this type with the specified name.
static DynamicSchemaFilter.NewColumnsMode[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

NONE

public static final DynamicSchemaFilter.NewColumnsMode NONE

No new columns are allowed at this level or in maps below this level. Occurs when the schema is defined or with a strict provided schema.

ALL

public static final DynamicSchemaFilter.NewColumnsMode ALL

New columns are allowed at this level and below. Occurs in a wildcard projection in which there are no constraints on the columns which can be added.

CHILD_ONLY

public static final DynamicSchemaFilter.NewColumnsMode CHILD_ONLY

New columns cannot be added at this level, but can be added in maps below this level. Occurs in a query where the projection list is explicit: a, b, m, and it turns out that m is a map. A simple m projection is logically equivalent to m.*.

This same logic can apply to maps if the project list contains something like m.a, m.m2, and m2 turns out to be a map.

Method Detail

values

public static DynamicSchemaFilter.NewColumnsMode[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DynamicSchemaFilter.NewColumnsMode c : DynamicSchemaFilter.NewColumnsMode.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DynamicSchemaFilter.NewColumnsMode valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null