In IBM DataStage jobs, which technique is commonly used to generate a sequential surrogate key or sequence number for each incoming row?

Introduction / Context:
Generating sequence numbers or surrogate keys is a common requirement in ETL processes, including those built with IBM DataStage. Surrogate keys are often used as primary keys in dimension tables or as unique identifiers for records in data warehouses. This question asks how such sequence numbers are typically generated within DataStage jobs.

Given Data / Assumptions:

• We are working in an IBM DataStage environment.
• Each incoming row needs a unique, incrementing key value.
• DataStage provides built-in components or routines to generate such keys.
• Manual editing or unrelated network tools are not appropriate solutions.

Concept / Approach:
DataStage supports several ways to generate sequence numbers. A common method is to use a Surrogate Key Generator or Sequence stage, which maintains a counter and assigns incrementing values to each row. Another approach is to use built-in routines or system variables (such as @INROWNUM in a Transformer stage) to generate row numbers. The key idea is that the sequence is generated automatically within the job, not by manual editing or unrelated external tools.

Step-by-Step Solution:
1. Identify the requirement: each processed row should receive a unique, sequential number that can serve as a surrogate key.2. Recognise that DataStage provides dedicated stages or routines, such as a Surrogate Key Generator, to handle this task reliably.3. When the job runs, the stage or routine maintains an internal counter and assigns the next value to each row as it flows through.4. Option A explicitly states that you use a Surrogate Key Generator (or Sequence) stage or routine that assigns an incrementing number to each row, which matches standard DataStage practice.5. Option B suggests manually typing numbers in an external text editor, which is not scalable or part of normal DataStage job design.6. Option C involves using a network router to assign IP addresses as sequence numbers, which is unrelated to ETL key generation.7. Option D suggests using a web browser to paste random numbers, again not an automated or reliable ETL technique.8. Therefore, Option A is the correct answer.

Verification / Alternative check:
DataStage tutorials and examples often demonstrate the creation of surrogate keys for dimension tables by adding a Surrogate Key Generator stage to the job design. Documentation also describes functions and stage properties that can generate incrementing values. These sources confirm that automatic sequence generation inside the job, not manual editing, is the accepted approach.

Why Other Options Are Wrong:
Option B is wrong because manual numbering outside DataStage is error-prone and does not support dynamic ETL workflows.Option C is wrong because network routers and IP address assignment are unrelated to DataStage surrogate key generation.Option D is wrong because using a browser to copy and paste numbers is not a DataStage feature and would not support large-scale or repeatable ETL processes.

Common Pitfalls:
One pitfall is not considering concurrency and restartability when generating keys; sequences must remain consistent even if jobs are rerun or processed in parallel. Another issue is relying on natural keys from source systems, which may change over time and complicate slowly changing dimension handling. Using a dedicated surrogate key mechanism within DataStage helps avoid these problems and maintains stable identifiers in the data warehouse.

Final Answer:
Use a Surrogate Key Generator (or Sequence) stage or routine that assigns an incrementing number to each row passing through the job.