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  1. Preface
  2. Mappings
  3. Mapplets
  4. Mapping Parameters
  5. Where to Assign Parameters
  6. Mapping Outputs
  7. Generate a Mapping from an SQL Query
  8. Dynamic Mappings
  9. How to Develop and Run a Dynamic Mapping
  10. Dynamic Mapping Use Cases
  11. Mapping Administration
  12. Export to PowerCenter
  13. Import From PowerCenter
  14. Performance Tuning
  15. Pushdown Optimization
  16. Partitioned Mappings
  17. Developer Tool Naming Conventions

Developer Mapping Guide

Developer Mapping Guide

Get Columns from the Data Source

Get Columns from the Data Source

You can update the ports in a Read transformation at run time based on the structure of the relational or flat file data source. You might use this method to update the run-time instance of the Read transformation.
Update the columns at run time when you expect small changes to the source. For example, you need to process a source from another organization, but the organization cannot guarantee the order of the columns in the source file. When you enable the option to update the data object columns at run time, the Data Integration Service changes the ports of the Read transformation based on the structure of the source data. The Read transformation passes the data to the downstream transformations in the dynamic mapping for processing.
When you update the data object columns at run time, the Data Integration Service updates a run-time instance of the Read transformation. It does not update metadata in the Model repository. To see the changes in the Developer tool, view the mapping with resolved parameters. To update the physical data object definition in the Model repository, use the synchronize option in the Developer tool. The Developer tool re-imports the physical data object metadata and changes the metadata.
You cannot use a custom SQL query in a dynamic mapping.
The following image shows where to enable the option on the
Data Object
tab:
The Data Object tab shows the Specify By option, the data object name, the data object description, and the type of data object. The tab has a checkbox that enables the option At runtime, get data object columns from data source
The Data Integration Service determines the structure of a relational source by the schema. It examines the schema of the resource that appears on the
Run-time
tab. The Data Integration Service then updates the columns in the transformation data object based on the schema.
The Data Integration Service determines the structure of a flat file source based on the way you configure the flat file physical data object. You configure the data object to generate column names at run time.
Configure this functionality on the
Data Object
tab of the Read transformation for a flat file or relational source.
For more information about setting the flat file physical data object properties, see the
Informatica Developer Tool Guide
.

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