IKM When Staging Area is on the Target Server FAQS

1. What is an IKM in Oracle Data Integrator?
An Incremental Knowledge Module (IKM) is a predefined set of instructions in Oracle Data Integrator (ODI) that facilitates the extraction, transformation, and loading (ETL) of data between source and target systems. It determines how data is moved from the staging area to the target system, and whether the data is appended, updated, or processed incrementally.

 

2. How does the IKM process work?
The IKM process typically follows these steps:

1. Execute a set-oriented SELECT statement to fetch and transform the data.
2. Write data to the target table (directly or via temporary "I$" tables).
3. Create and manage temporary tables for complex transformations.
4. Validate the data against target constraints (using Check Knowledge Modules, CKMs).
5. Write the final cleansed data to the target system.
6. Drop temporary tables to clean up.
7. Optionally, a final consistency check ensures data integrity.

 

3. What is the difference between simple and complex IKMs?

• Simple IKMs: These are typically used when data is being appended to the target system without requiring any intermediate transformations or validation. The transformed result set is directly written into the target table.
• Complex IKMs: These involve additional steps such as creating a temporary "I$" table to store intermediate results, performing data validation, and handling errors before the final data is written to the target system.

 

4. What is the role of the "I$" table in complex IKMs?
In complex IKMs, the "I$" table acts as a temporary storage space for the result set before the data is inserted into the target table. This allows for additional processing like data validation, error handling, or performing incremental updates before the final data is committed to the target system.

 

5. How are target constraints checked in the IKM process?
During the IKM process, if target constraints are defined, a Check Knowledge Module (CKM) is used to validate the data. The CKM checks the data against business rules or constraints (e.g., primary keys, uniqueness, referential integrity). Invalid data is either removed or corrected before being written into the target system.

 

6. Can the IKM process be customized?
Yes, the IKM process can be customized in ODI. You can create or modify your own IKMs to meet specific data integration requirements, such as custom error handling, validation rules, or transformation logic. However, ODI also comes with a wide range of pre-built IKMs for different use cases, like incremental updates, SCD (Slowly Changing Dimensions), and more.

 

7. What does "set-oriented processing" mean in the context of IKMs?
Set-oriented processing refers to processing data in bulk rather than row by row. This is more efficient, particularly for large datasets. Instead of processing one record at a time, the IKM applies operations to entire sets of data in one go, maximizing the speed of data movement and transformation.

 

8. What are the benefits of using IKMs in Oracle Data Integrator?

• Efficiency: IKMs maximize performance by processing data in sets, which is ideal for large-scale ETL processes.
• Flexibility: IKMs support a wide variety of data integration use cases, from simple loads to complex data transformations and validations.
• Error Handling: IKMs, especially complex ones, allow for data validation and error isolation, ensuring high-quality data is loaded into the target system.
• Resource Management: Temporary tables ("I$" tables) help manage resources more effectively, ensuring that large datasets are processed without overloading the system.

 

9. How does IKM handle incremental updates?
IKMs can be configured to handle incremental updates by only loading the new or changed data since the last load. This is typically achieved by comparing the source and target data, identifying differences (such as new or updated records), and applying changes to the target system without reloading the entire dataset.

 

10. Can IKMs be used for Slowly Changing Dimensions (SCD)?
Yes, certain IKMs in ODI are specifically designed for handling Slowly Changing Dimensions (SCD). These IKMs allow you to manage changes in dimensional data over time, such as maintaining historical records for changed attributes. The logic for SCD Type 1, Type 2, and Type 3 updates can be embedded in the IKM process.

 

11. What happens after the IKM has finished its process?
Once the IKM completes the data processing and loading:

1. It ensures that the data in the target system is consistent with the defined constraints.
2. Temporary tables ("I$" tables) are dropped.
3. Optionally, a final consistency check can be performed to verify that all data transformations and loads were successful.

 

12. How can you monitor and troubleshoot IKMs?
Monitoring and troubleshooting can be done by reviewing:

• ODI session logs: These logs contain detailed information about the IKM’s execution, including any errors encountered during the process.
• Execution plans: The plan helps in understanding how each step of the IKM is executed and can help pinpoint issues.
• Error tables: If there is error handling configured, the erroneous records are logged in error tables, which can be reviewed and fixed.