15.00 - Storage Structure of a Structured UDT Data Type - Teradata Database

Teradata Database Design

Teradata Database
User Guide

Storage Structure of a Structured UDT Data Type

The following graphic illustrates the basic morphology of a structured UDT as it is stored in the row of a table in the Teradata Database:



UDT element …

Specifies …

Type ID

the TVMID type identifier for the structured UDT.

Its data type is INTEGER (4 bytes).

Presence Bits Array

the octet array of presence bits for the UDT at level m of the structured UDT.

This is a variably‑sized bit array, rounded to the higher modulo(8) boundary, whose size depends on the number of attributes stored for a particular structured UDT. Its size increases in octet (8‑bit byte) increments.

Attribute n Value

attribute number n for the structured UDT.

There is a variable number of attribute value fields. The exact number depends on two factors:

  • The number of attributes a particular structured type has.
  • Whether or not an attribute is null.
  • The exact format of each attribute depends on the attribute type and is defined by the designer of the given structured type.