Package org.apache.calcite.rel.type

Enum StructKind

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<StructKind>
    public enum StructKind
extends java.lang.Enum<StructKind>
    Describes a policy for resolving fields in record types.

    The usual value is FULLY_QUALIFIED.

    A field whose record type is labeled PEEK_FIELDS can be omitted. In Phoenix, column families are represented by fields like this. PEEK_FIELDS_DEFAULT is similar, but represents the default column family, so it will win in the event of a tie.

    SQL usually disallows a record type. For instance, 

    SELECT address.zip FROM Emp AS e

    is disallowed because address "looks like" a table alias. You'd have to write 

    SELECT e.address.zip FROM Emp AS e

    But if a table has one or more columns that are record-typed and are labeled PEEK_FIELDS or PEEK_FIELDS_DEFAULT we suspend that rule and would allow address.zip.

    If there are multiple matches, we choose the one that is:

    1. Shorter. If you write zipcode, address.zipcode will be preferred over product.supplier.zipcode.
    2. Uses as little skipping as possible. A match that is fully-qualified will beat one that uses PEEK_FIELDS_DEFAULT at some point, which will beat one that uses PEEK_FIELDS at some point.

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description
      FULLY_QUALIFIED
      This is a traditional structured type, where each field must be referenced explicitly.
      NONE
      This is not a structured type.
      PEEK_FIELDS
      If a field has this type, you can see its fields without qualifying them with the name of this field.
      PEEK_FIELDS_DEFAULT
      As PEEK_FIELDS, but takes priority if another struct-typed field also has a field of the name being sought.
      PEEK_FIELDS_NO_EXPAND
      As PEEK_FIELDS, but fields are not expanded in "SELECT *".

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      private StructKind()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static StructKind valueOf​(java.lang.String name)
      Returns the enum constant of this type with the specified name.
      static StructKind[] 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 StructKind NONE
        This is not a structured type.

      • FULLY_QUALIFIED

        public static final StructKind FULLY_QUALIFIED
        This is a traditional structured type, where each field must be referenced explicitly.

        Also, when referencing a struct column, you need to qualify it with the table alias, per standard SQL. For instance, SELECT c.address.zipcode FROM customer AS c is valid but SELECT address.zipcode FROM customer it not valid.

      • PEEK_FIELDS_DEFAULT

        public static final StructKind PEEK_FIELDS_DEFAULT
        As PEEK_FIELDS, but takes priority if another struct-typed field also has a field of the name being sought.

        In Phoenix, only one of a table's columns is labeled PEEK_FIELDS_DEFAULT - the default column family - but in principle there could be more than one.

      • PEEK_FIELDS

        public static final StructKind PEEK_FIELDS
        If a field has this type, you can see its fields without qualifying them with the name of this field.

        For example, if address is labeled PEEK_FIELDS, you could write zipcode as shorthand for address.zipcode.

      • PEEK_FIELDS_NO_EXPAND

        public static final StructKind PEEK_FIELDS_NO_EXPAND
        As PEEK_FIELDS, but fields are not expanded in "SELECT *".

        Used in Flink, not Phoenix.

    • Constructor Detail

      • StructKind

        private StructKind()

    • Method Detail

      • values

        public static StructKind[] 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 (StructKind c : StructKind.values())
    System.out.println(c);
        Returns:
        an array containing the constants of this enum type, in the order they are declared

      • valueOf

        public static StructKind valueOf​(java.lang.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:
        java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
        java.lang.NullPointerException - if the argument is null