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Companies are investing in solutions like Informatica, and there is a significant demand for qualified developers who can utilize these tools for improved business insights. With rising technology advancements, heightened competition, and requirements for topmost skill-sets, thorough preparation is vital for nailing your interview. We've collected the best Informatica interview questions and answers to guide you when preparing for your final showdown day.
Performance of the aggregator improves dramatically when records are sorted well before they are passed to the aggregator. Here, you can use Group by clause to sort records.
For this purpose, you should check the Distinct option of the Source qualifier in the source table and load the target accordingly.
To answer these Informatica Interview Questions:
Lookup Cache is either static or dynamic in nature. A static lookup cache cannot be modified once it is built and remains the same during the session run. A dynamic cache can be modified during the session run, and you can modify the database based on the incoming data source. A lookup cache can be either persistent or non-persistent based on whether Informatica retains the Cache even after the session run is complete or remains pending.
Yes, it is possible updating a target table without using the update strategy. For this purpose, we should define the key first then connect the key with the respective field that you want to update.
Here is the Answer to these Informatica Interview Questions
The code page contains encoding to specify characters in a set of multiple columns. A code page is selected based on the source of the data. It influences the way how application stores, receives and sends the character data.
Answer this Informatica Interview Questions like here:
It is a crucial transformation that is required to maintain the history data or just the most recent changes in the target table. Here, we can set or flag the records using two levels.
Aggregate calculations like sum, average, maximum, minimum are the measure objects.
You can use either file repository or Union operator to copy multiple files to a single target.
In a star schema, there is no relationship between dimension tables or relational tables. All dimensions are denormalized, and query performance is degraded.
Answer to this Informatica Interview Questions:
In the snowflake schema, there is a possible relationship between dimension tables or relational tables. All dimensions are normalized, and query performance is increased.
Here is the Top-Down Approach for Data Warehouse:
ODS --> ETL --> Datawarehouse --> DataMart --> OLAP
Here is the bottom-up approach for Data Warehouse:
ODS --> ETL --> DataMart --> Datawarehouse --> OLAP
Performance can be improved by creating multiple partitions and processing data in parallel. Informatica can achieve high performance by partitioning the pipeline and perform loading, extraction, and transformation for each partition in parallel.
You should use an unconnected lookup here if the same lookup repeats multiple times.
Yes, we can use Informatica for data cleansing. Here, you can use either stages or expressions for data cleaning. You can use constant values or assign space for avoiding session failures.
It is not possible creating or importing flat files directly to the warehouse designer quickly. Instead, you should analyze files in the source analyzer first and drag those files into the warehouse designer. When these files are dragged, the warehouse designer will create a file definition, not the relational target definition. To load a file, configure the session to write to a flat file. When the Informatica server runs the session, it creates and loads the flat file.
A fact table is demoralized in nature that stores the data from the dimension table generally contains foreign keys and measures.
If you are talking about flat files, then you can set the same in file properties. If you want to add headers and footers at the session level, then check the session properties.
The major components of Informatica server architecture are load manager, data transfer manager, temp server, reader, and writer, etc. Load manager sends a request to the reader, if the reader is ready to read the data from the source then it is stored to the temp server, and the data transfer manager takes the data from the temp server and loads it to the target.
These are the common steps to follow for configuring mapping in Informatica.
To Improve the Performance, You Should Use These Tips:
The possible number of dimensions available in Informatica can be given as:
In Informatica 8.0, the power exchange concept is introduced that was not available in Informatica 7.0.
It specifies the directory that can be used to cache the master records and set indexes to these records. This directory can be mapped with a mounted drive. These are two types of joiner caches in Informatica. These are Data Cache and Index Cache.
Filter transformation is an active transformation, and Lookup transformation is passive transformation. Filter transformation is used to filter rows based on specified conditions, and lookup transformation is used to lookup data in a relational table or a flat file.
If there is a well-defined source, then you should use connected lookup, if the source is not defined well then you can use unconnected lookup in that case. When you look up a single value among thousands, then you should use an unconnected lookup here. If multiple columns are returned, then opt for a connected lookup in that case.
It is expression transformation or unconnected lookup.
With the load order utility, you may find the rejected data from the bad file and make the corrections as required.
A joiner transformation compares each row of the master source against the detail source. There are a few unique rows and iterations in the master that speed up the join process. Joiner Transformation caches the master table data, so you should define only a selected number of rows as the master.
For this purpose, create one procedure and declare a sequence inside the procedure. Now call the procedure in the Informatica using stored procedure transformation to access the top 100 rows from the flat file to the target.
To import the Oracle sequence in Informatica, first, create one procedure and declare a sequence within the procedure. Now call the procedure in Informatica with the help of stored procedure transformation.
Here you can use SCD type 1/2/3 to load dimensions based on requirements. We can also use procedures to populate time dimensions.
Yes, it is available in Informatica 8.0 version.
In hash partitioning, the Informatica Server uses a hash function to group multiple rows of data among partitions. The data rows are grouped together based on a partition key. For example, you want to group multiple items together in a table having the same ID number without knowing it in advance.
By default, flat files support only numbers, no decimal places. To support the decimal places in Informatica, you should define a data type as decimal for that number port of the source.
Source -> Number Port -> Decimal Data Type
First of all, import fields as a string then use expressions to convert it. You should avoid truncation if there are decimal places in the source itself.
In the case of Incremental aggregation, Informatica passes the source data through mapping and utilizes the historical data to perform new aggregation calculations incrementally to improve the performance. When the source changes incrementally, it can capture changes and able to process those changes. In this way, the target can be updated incrementally instead of modifying each record one by one that is highly time-consuming.
A Target Load Order is the collection of source qualifiers, transformations, and targets that are connected together through mapping. Target load order can be specified based on source qualifiers in a mapping. If multiple source qualifiers are connected to different targets, then you can set an order in which the Informatica server loads data into targets.
If multiple sessions in a concurrent batch fail, there is a possibility of truncating all targets and run them again. At the same time, if a particular session in a concurrent batch fails, then all other sessions can be executed successfully. However, that particular session can be recovered later as a standalone session.
Here is the process of how to recover a failure session in Informatica:
Under specific conditions, if a session does not complete, you should truncate the target tables and run sessions from the beginning. When running sessions for recovery, it may result in inconsistent data sometimes. If there is no recovery option for the session in the mid then:
When you are adding a relation or flat-file definition to the mapping, it is first connected to a Source Qualifier. A source qualifier represents the rows that Informatica Server reads and executes a session.
Partition points in Informatica mark the thread boundaries in a source pipeline and divide pipelines into stages further.
The best idea is to use sorted inputs for Aggregator Transformation. If data cannot be sorted due to any issue, then configure the cache and set indexes to it.
This article, "Top 50 Informatica interview questions and Answers," provides an in-depth look at the types of questions you'll be asked during an Informatica interview. This is just a starting point; the interviewer can ask a lot more questions. Join the SQL certification course at JanBask Training to gain a thorough understanding of it and to ensure that you are future-ready in the IT sector.
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