Table of Contents

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  1. Preface
  2. Introduction to PowerExchange for HDFS
  3. PowerExchange for HDFS Configuration
  4. HDFS Connections
  5. HDFS Data Objects
  6. HDFS Data Extraction
  7. HDFS Data Load
  8. HDFS Mappings
  9. Appendix A: Data Type Reference

PowerExchange for HDFS User Guide

PowerExchange for HDFS User Guide

Schema Properties

Schema Properties

The Developer tool displays the schema properties for intelligent structure model, Avro, JSON, ORC and Parquet complex file sources in the Properties view of the
Read
operation.
The following table describes the Schema properties that you configure for the complex file sources:
Property
Description
Column Name
Displays the name of the column.
Column Type
Displays the format of the column.
Enable Column Projection
Displays the column details of the complex files sources.
Schema Format
Displays the schema format that you selected while creating the complex file data object. You can change the schema format and provide respective schema.
You can select one of the following options:
  • Avro
  • Json
  • Orc
  • Parquet
  • Xml
  • Intelligent Structure Model
  • Assign Parameter
You can change the complex file format without losing the column metadata even after you configure the column projection properties for another complex file format.
You can parameterize the schema format using the
Assign Parameter
option.
You can switch from one schema format to another only once. If you change the schema format more than once, you might lose the original datatypes.
Schema
Displays the schema associated with the complex file. You can select a different schema.
You can select one of the following options:
  • Browse
  • Assign Parameter
  • Assign Path as Parameter
For the Assign Path as Parameter option, the path can be obtained from the server.
When you use Refresh Schema for the source or target in a mapping and also, parameterize the schema, the parameterized schema takes precedence over the refresh schema.
  • If you disable the column projection, the schema associated with the complex file is removed. If you want to associate schema again with the complex file, enable the column projection and click Select Schema.
  • When you parameterize the schema in a Parquet complex file, the schema should not contain a String data type, use UTF8 data type instead.
Column Mapping
Displays the mapping between input and output ports.
If you disable the column projection, the mapping between input and output ports is removed. If you want to map the input and output ports, enable the column projection and click Select Schema to associate a schema to the complex file.
In the native environment, Data Preview and a mapping may fail in the following scenarios:
  • When you import an Avro file as a source object and switch the schema format to Parquet and select a Parquet file as the source object.
  • When you import a JSON file as a source object and switch the schema format to Avro and select an Avro file as the source object.
You must edit the schema as per the selected schema format or enable the refresh schema at runtime option in the mapping if you want to change the schema format.

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