Important Informatica Questions & Answers
Question.1 What is change data capture?
Answer: Change Data Capture (CDC) helps identify the data in the source system that has changed since the last extraction. With CDC, data extraction takes place at the same time the insert, update , or delete operations occur in the source tables, and the change data is stored inside the database in change tables. The change data, thus captured, is then made available to the target systems in a controlled manner.
Question.2 How can we store previous session logs.
Answer: Just run the session in timestamp mode then automatically session log will not overwrite the current session log. We can do this way also Using SPM Session log count (specify the number of runs of the session log to save)
Question.3 How to define the INFORMATICA server?
Answer: INFORMATICA server is the main server component in the INFORMATICA product family, which is responsible for reads from the various source systems and transforms the data according to business rule and loads the data into the target table.
Question.4 How to move the mapping from one database to another?
Answer: U can also do it this way connect to both the repositories, open the respective folders, keep the destination repository as active from the navigator panel just drag the mapping to the work area. it will ask whether to copy the mapping say YES. it’s done.
Question.5 Is a fact table normalized or de—normalized?
Answer: A fact table is always the DENORMALISED table. It consists of data from the dimension table (Primary Key’s )and the Fact table has Foreign keys and measures.
Question.6 How can we join 3 databases like Flat File, Oracle, Db2 in INFORMATRICA.,
Answer: Using Joiner Transformation.
Question.7 How do we analyze the data at the database level?
Answer: Data can be viewed using INFORMATICA’S designer tool. If you want to view the data on source /target we can preview the data but with some Limitations. We can use data profiling too.
Question.8 How U will create header and footer in the target using the information?
Answer: If you are the focus is about the flat files then one set it in file properties while creating a mapping or at the session level in session properties.
Question.9 How to export mappings to the production environment?
Answer: How to export mappings to the production environment?
Question.10 How to Generate the Metadata Reports in INFORMATICA?
Answer: You can generate Power Center Metadata Reporter from a browser on any workstation, even a workstation that does not have Power Center tools installed.
Question.11 How can we eliminate duplicate rows from a flat-file?
Answer: Before loading to target, use an aggregator transformation and make use of group by function to eliminate the duplicates on columns. Or U can use sorter transformation or Rank Transformation to eliminate duplicates from flat files.
Question.12 What is Partitioning? where we can use Partition? What are the advantages? Is it necessary?
Answer: The Partitioning Option increases Power Center’s performance through parallel data processing, and this option provides a thread —-based architecture and automatic data partitioning that optimizes parallel on multiprocessor and grid-based hardware environments.
Question.13 What is a surrogate key? In ur project in which situation U has the situation u have used? explain with example?
Answer: A surrogate key is system generated /artificial key /sequence number or A surrogate key is a substitution for the natural primary key. It is just a unique identifier or number for each row that can be used for the Primary key to the table. The only requirement for a surrogate primary key is that it is unique for each row in the table it is useful because the natural primary key (i.e. Customer Number in Customer table) can change and this makes updates more difficult but In my project, I felt that the primary reason for the surrogate keys was to record the changing context of the dimension attributes., (particularly for sod ) The reason for them being integer and integer joins are faster.
Question.14 What is the diff b/w STOP & ABORT in the INFORMATICA session level?
Answer: Stop: We can Restart the session. Abort WE cant restart the session. We should truncate all the pipeline after that start the session.
Question.15 If the workflow has 5 sessions and running sequentially and 3 rd session has been failed how can we run again from the only 3rd to 5 TH session?
Answer: If multiple sessions in a concurrent batch fail, you might want to truncate all targets and run the batch again , However, if a session in a concurrent batch fails and the rest of the sessions complete successfully, you can recover the session as a standalone session. To recover a session in a concurrent batch: 1, Copy the failed session using Operations—Copy Session.2. Drag the copied session outside the batch to be a standalone session.3. Follow the steps to recover a standalone session.4. Delete the standalone copy.
Question.16 What is meant by EDW?
Answer: Its a big data warehouses OR centralized data warehousing OR the old style of the warehouse .It’s a single enterprise data warehouse (EDW) with no associated data or operational data store (ODS)
Question.17 In real-time which one is better to star scheme or snowflake star schema, the surrogate will be linked to which columns in the dimension table.
Answer: In a real-time only star schema will implement because it will take less time and the surrogate key will there in each and every dimension table in a star schema and this surrogate key will assign as a foreign key in fact table.
Question.18 Can batches be copied /stopped from the server manager?
Answer: Yes, we can stop the batches using the server manager or PMCMD command.
Question.19 What are the real-time problems generally come up while doing//running mapping /any transformation?
Answer: Maybe you will encounter with connection failure, other then that I don’t think so, conserve will handle all the syntax errors and Invalid mappings.