Column Generator

 

The Column Generator is a Processing (active) stage in Data Stage used to create new columns or assign calculated/constant values to existing columns without writing complex Transformer logic.

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What does Column Generator do?

It allows you to:

• Add new columns
• Assign constant values
• Perform simple expressions
• Generate system-based values (date, timestamp, job name, etc.)

It works row by row, just like a lightweight Transformer.

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Common use cases

1️. Add constant values

COUNTRY = 'INDIA'

SOURCE_SYSTEM = 'HR_APP'

2️. Add system-generated values

LOAD_DATE = CURRENT_DATE

LOAD_TS   = CURRENT_TIMESTAMP

JOB_NAME  = DSJOBNAME

3️. Simple calculations

TOTAL_SALARY = BASIC + HRA + BONUS

TAX_AMOUNT   = SALARY * 0.1

4️. Create audit columns (very common in ETL)

• CREATED_DATE
• UPDATED_DATE
• BATCH_ID
• RUN_ID

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When to use Column Generator vs Transformer

Column Generator	Transformer
Simple logic	Complex logic
Constants & basic expressions	IF-ELSE, Lookups
Faster & lightweight	More flexible
Easy to configure	More control

Best practice:
Use Column Generator for simple additions and Transformer only when logic becomes complex.

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Key points to remember

• It does not filter rows
• It does not change row count
• Expressions use Data Stage expression language
• Cannot perform lookup or joins

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Simple example flow:

Sequential File

      |

Column Generator

(Add LOAD_DATE, BATCH_ID)

      |

Target Table

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