Table of Contents

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  1. Preface
  2. Introduction to Data Transformation
  3. Data Processor Transformation
  4. Wizard Input and Output Formats
  5. Relational Input and Output
  6. Using the IntelliScript Editor
  7. XMap
  8. Libraries
  9. Schema Object
  10. Command Line Interface
  11. Scripts
  12. Parsers
  13. Script Ports
  14. Document Processors
  15. Formats
  16. Data Holders
  17. Anchors
  18. Transformers
  19. Actions
  20. Serializers
  21. Mappers
  22. Locators, Keys, and Indexing
  23. Streamers
  24. Validators, Notifications, and Failure Handling
  25. Validation Rules
  26. Custom Script Components

Overview of Locators, Keys, and Indexing

Overview of Locators, Keys, and Indexing

In designing a transformation, a frequent issue is how to locate the data holders that you want to process. If the same data holders can occur multiple times in an XML structure, there can be ambiguities in identifying the occurrences. This chapter explains how to use the
Locator
and
Key
components to resolve the ambiguities.
The components described in this chapter let you identify the occurrences of multiple-occurrence data holders in three ways:
  • Sequentially. Each iteration of a component processes the next occurrence of the data holder.
  • By occurrence number. For example, a component can select the third occurrence of a data holder.
  • By a key such as an attribute or a nested element. The key uniquely identifies the occurrence of the data holder.
The sequential approach is the default. It is subject to some complexities that you can control by using the
Locator
component.
The occurrence number and key approaches are collectively known as indexing. The term is analogous to the index of a book, where you use a page number or a subject key to identify the location of information. You can implement the indexing by using components called
LocatorByOccurrence
,
LocatorByKey
, and
Key
.
You can use the locator and key components in parsers, serializers, or mappers. You can use the components to identify the occurrences of data holders in the input, the output, or both.
The locator components are nested in the
source
and
target
properties of various transformation components. The meaning and usage of the
source
and
target
properties is explained below.


Updated June 14, 2019