The STRUCTURE Command

The STRUCTURE command builds the internal indexes for keyed fields. The FIND and MATCH commands use these indexes to achieve their speed.

Notation standards

Options

Answers

Syntax:

Form1:	STRUCTURE/options [<key-name>]
Form2:	STRUCTURE/Cnnn <key-name1> [ ... <key-nameN>]

Options:
                P              -Build add-on structure to existing structure (obsolete)
                X             -Suppress the command response
                Y             -Do not alter the command answer cells

Answers:
                Ctl.Ans1                =Zero
                Ctl.Ans2                =Zero
                Ctl.Ans3                =Zero

Notes:
(1) Form1 is the general STRUCTURE Command. It will perform initial build and incremental build for all types of indexes.

(2) Form2 is optimized for low-cardinality indexes. It is substantially faster than Form1. And it allows multiple indexes to be built with a single pass of the data.

Cardinality refers to the uniqueness quality of the key; that is, the number of unique values in the index. Form2 gives excellent performance up to an aggregate cardinality of 50,000 or more. The only qualification is that it requires approximately 8K bytes of memory times the maximum cardinality.

The parameter nnn is an estimate of the maximum aggregate cardinality. In earlier versions of Thunderbolt, there was no forgiveness if this value was exceeded. However, in the current version, the required resources are automatically adjusted if this value is exceeded.

(3) The /P option is no longer required with the STRUCTURE command to differentiate between an initial build and an incremental build. The proper context is detected automatically by both Form1 and Form2; and appropriate actions are taken.

(4) The STRUCTURE Command requires access to all tables in a data base. It will fail if it is used with an Application Interface in which the view has been restricted with the "DATA GROUPS ARE ..." declaration.

STRUCTURE Usage

STRUCTURE Vs CONSTRUCT

Advanced STRUCTURE Command Functionality