Top 50 Informatica Interview Questions & Answers
1. What is Informatica PowerCenter?
Answer: Informatica PowerCenter is an industry-leading data integration platform that enables organizations to extract, transform, and load (ETL) data from various sources to target systems. It offers a comprehensive suite of tools for data warehousing, data quality, data replication, and more.
2. Explain the architecture of Informatica PowerCenter.
Answer:
- Repository: Centralized metadata repository storing all project-related information.
- Integration Service: Executes workflows and transformations.
- Repository Service: Provides access to the repository for other components.
- Workflow Monitor: Tracks workflow execution status, logs, and performance.
- PowerCenter Designer: GUI for designing and developing workflows.
3. What are the different types of transformations in Informatica?
Answer:
- Active: Modify data actively (e.g., Expression, Filter, Joiner, Aggregator)
- Passive: Pass data through with minimal modification (e.g., Router, Sorter, Union)
- Lookup: Retrieve data from external sources (e.g., Lookup, Index)
4. What is a workflow in Informatica?
Answer: A workflow is a collection of tasks that execute in a defined sequence to achieve a specific data integration objective.
5. Explain the concept of sessions in Informatica.
Answer: Sessions are the smallest executable units within a workflow. Each session executes a specific task, such as loading data from a source to a target.
6. What are the different types of sessions in Informatica?
Answer:
- Command Task: Executes operating system commands.
- PL/SQL Task: Executes PL/SQL code.
- Workflow Task: Executes another workflow.
- Data Flow Task: Executes a data flow, which contains transformations.
7. What is a data flow in Informatica?
Answer: A data flow is a graphical representation of the data movement and transformation within a session.
8. What are sources and targets in Informatica?
Answer:
- Source: The origin of the data (e.g., database, flat file, web service).
- Target: The destination of the data (e.g., database, flat file, data warehouse).
9. Explain the concept of mappings in Informatica.
Answer: Mappings define the business logic for transforming data from source to target. They consist of sources, targets, and a series of transformations.
10. What are the different types of indexes in Informatica?
Answer:
- Lookup Index: Used to improve the performance of Lookup transformations.
- Sort Index: Used to improve the performance of sorting operations.
11. What is a reusable transformation in Informatica?
Answer: A transformation that can be used in multiple mappings within a project or even across projects.
12. Explain the concept of partitioning in Informatica.
Answer: Dividing large datasets into smaller, more manageable chunks to improve performance and resource utilization.
13. What are the different types of partitioning in Informatica?
Answer:
- Horizontal Partitioning: Divides data rows among multiple sessions.
- Vertical Partitioning: Divides data columns among multiple sessions.
14. What is data profiling in Informatica?
Answer: The process of analyzing data characteristics to understand its quality, identify anomalies, and determine appropriate transformation strategies.
15. What is data quality in Informatica?
Answer: Ensuring data accuracy, completeness, consistency, and validity to support business decisions.
16. What are some common data quality issues?
Answer:
- Data duplication
- Missing values
- Inconsistent data formats
- Invalid data
17. How can you handle data quality issues in Informatica?
Answer:
- Data cleansing transformations (e.g., Expression, Filter)
- Data validation rules
- Data profiling tools
18. What is a lookup transformation?
Answer: Retrieves data from an external source (e.g., database table, flat file) based on a lookup condition.
19. What is a joiner transformation?
Answer: Combines data from two or more sources based on a join condition.
20. What is an aggregator transformation?
Answer: Performs aggregate functions on groups of data (e.g., SUM, AVG, COUNT).
21. What is a filter transformation?
Answer: Selects rows that meet specific criteria.
22. What is an expression transformation?
Answer: Applies complex calculations and data manipulations using expressions.
23. What is a router transformation?
Answer: Directs data rows to different output groups based on defined conditions.
24. What is a sorter transformation?
Answer: Sorts data rows based on one or more columns.
25. What is a union transformation?
Answer: Combines data from multiple sources into a single output.
26. What is a source qualifier transformation?
Answer: Defines the connection to the source system and retrieves data.
27. What is a target definition transformation?
Answer: Defines the target system and how data should be loaded.
28. What is a session property?
Answer: A configuration parameter that controls the behavior of a session.
29. What are some common session properties?
Answer:
- Parallelism
- Deadlock timeout
- Buffer size
- Error handling
30. What is a workflow monitor?
Answer: A tool that tracks the execution status, logs, and performance of workflows.
31. How can you monitor workflow execution?
Answer:
- Workflow Monitor
- Logs
- Performance graphs
32. What is a repository in Informatica?
Answer: A centralized database that stores all project-related metadata.
33. What are the different types of repositories in Informatica?
Answer:
- Oracle
- SQL Server
- DB2
34. What is a domain in Informatica?
Answer: A named collection of related data types and data values.
35. What is a folder in Informatica?
Answer: A container for organizing and managing project objects.
36. What is a parameter file in Informatica?
Answer: A file that stores session and workflow parameters, allowing for dynamic configuration and reusability.
37. What is a command task in Informatica?
Answer: Executes operating system commands within a workflow.
38. What is a PL/SQL Task in Informatica?
Answer: Executes PL/SQL code within a workflow.
39. What is a workflow task in Informatica?
Answer: Executes another workflow within a workflow.
40. What is a scheduler in Informatica?
Answer: Schedules the execution of workflows and sessions according to a predefined schedule.
41. What is an error handling strategy in Informatica?
Answer: Defines how the session or workflow should handle errors (e.g., stop, continue, redirect).
42. What is a rollback in Informatica?
Answer: Reverts the changes made by a session or workflow in case of errors.
43. What is a checkpoint in Informatica?
Answer: A point in the session execution where the session’s state is saved, allowing for recovery from failures.
44. What is data warehousing?
Answer: The process of collecting, integrating, and storing data from various sources to support business intelligence and decision-making.
45. What is ETL in the context of data warehousing?
Answer:
- Extract data from various sources (e.g., databases, flat files).
- Transform: Transform data into a consistent format and quality.
- Load: Load data into the data warehouse.
46. What is a star schema?
Answer: A data warehousing schema with a central fact table surrounded by dimension tables.
47. What is a snowflake schema?
Answer: An extension of the star schema where dimension tables are further normalized.
48. What is data cleansing?
Answer: The process of identifying and correcting data errors and inconsistencies.
49. What is data masking?
Answer: The process of obscuring sensitive data while preserving its original structure and format.
50. What are the benefits of using Informatica PowerCenter?
Answer:
- Increased data integration efficiency
- Improved data quality
- Enhanced data governance
- Improved data access
- Reduced development time and costs
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