INFORMATICA REALTIME INTERVIEW QUESTIONS :
1) Tell about mapplets in informatica?
Informatica Mapplets is a set of transformations that you will create in mapplets designer and you
use in multiple mappings .
2) Why use connectivity repository? Informatica powercenter
When you modify, schedule the session each time, informatica server communicates directly the repository in order to verify whether or not the session and valid users. All sessions and the mappings metadata will be stored in repositor
3) What is the process of DTM? Informatica powercenter
Once the crib of load performs validations for the session, it creates the DTM process. DTM is to create and manage threads that perform the tasks of the session. I have created the main thread. Master thread creates and manages all other threads.
4) What are the different threads in the process of DTM? Informatica powercenter
Master thread:to creates and manages all other threads in dtm
Mapping thread: a thread of mapping will be created for each session. Excerpt from session and mapping information
Son of pre and post session: this is going to be created to perform pre and post operations of the session.
Reader thread: a thread is created for each partition of a source.It reads the data from the source.
Writer thread: it will be created to load data to the target.
Wire processing: it will be created to transform the data.
5) What are session parameters? Informatica powercenter
Ans) Session settings such as mapping parameters r, represent values U can change between sessions, such as connections, database or source files.
Server Manager also allows you to create user-defined settings. Following the user defined r session settings.
Database connections
Source file names: use this setting when you want to change the name or the location of the source Session between the session file is running
Target file name: use this setting when you want to change the name or location of the target session between the session file is running.
Reject file name: use this setting when you want to change the name or place of meeting reject files between session runs.
6) Tell about Transformations in Informatica?
Informatica is a repository object that generates, modifies or is transmitting data.
7) What is override sql in Informatica?
Ans ) SQL override in Informatica to improve the performance of the Lookup transformation. We write the query that is already executed by Informatica. Here we use the join queries
8) How are you handling errors in Informatica?
Ans: debugger we can do
9) What are the different market ETL tools?
Ans) datastage,informatica AB initio, Oracle Warehouse Builder
10) What are the differences between the transformation of Carpenter and source qualifier transformation?
Ans) Heterogeneous data sources .In joiner transformation can be attached, but this can be achieved in the case of source qualifier transformation.
We need matching keys to join two sources relational in source qualifier transformation while it is not necessary incase of Carpenter. Two relational sources must come from the same source of data in source qualifier. We join the relational sources that come from different sources also.
1) Tell about mapplets in informatica?
Informatica Mapplets is a set of transformations that you will create in mapplets designer and you
use in multiple mappings .
2) Why use connectivity repository? Informatica powercenter
When you modify, schedule the session each time, informatica server communicates directly the repository in order to verify whether or not the session and valid users. All sessions and the mappings metadata will be stored in repositor
3) What is the process of DTM? Informatica powercenter
Once the crib of load performs validations for the session, it creates the DTM process. DTM is to create and manage threads that perform the tasks of the session. I have created the main thread. Master thread creates and manages all other threads.
4) What are the different threads in the process of DTM? Informatica powercenter
Master thread:to creates and manages all other threads in dtm
Mapping thread: a thread of mapping will be created for each session. Excerpt from session and mapping information
Son of pre and post session: this is going to be created to perform pre and post operations of the session.
Reader thread: a thread is created for each partition of a source.It reads the data from the source.
Writer thread: it will be created to load data to the target.
Wire processing: it will be created to transform the data.
5) What are session parameters? Informatica powercenter
Ans) Session settings such as mapping parameters r, represent values U can change between sessions, such as connections, database or source files.
Server Manager also allows you to create user-defined settings. Following the user defined r session settings.
Database connections
Source file names: use this setting when you want to change the name or the location of the source Session between the session file is running
Target file name: use this setting when you want to change the name or location of the target session between the session file is running.
Reject file name: use this setting when you want to change the name or place of meeting reject files between session runs.
6) Tell about Transformations in Informatica?
Informatica is a repository object that generates, modifies or is transmitting data.
7) What is override sql in Informatica?
Ans ) SQL override in Informatica to improve the performance of the Lookup transformation. We write the query that is already executed by Informatica. Here we use the join queries
8) How are you handling errors in Informatica?
Ans: debugger we can do
9) What are the different market ETL tools?
Ans) datastage,informatica AB initio, Oracle Warehouse Builder
10) What are the differences between the transformation of Carpenter and source qualifier transformation?
Ans) Heterogeneous data sources .In joiner transformation can be attached, but this can be achieved in the case of source qualifier transformation.
We need matching keys to join two sources relational in source qualifier transformation while it is not necessary incase of Carpenter. Two relational sources must come from the same source of data in source qualifier. We join the relational sources that come from different sources also.
11)
What are the metadata of source that should be imported while importing
the relational source definition from database?
Ans) The metadata of source that should be imported are:
Column names
Key constraints
Database location
Key constraints
Database location
Source name
Data types
Data types
12) In
connected and unconnected lookup transformations when do we use dynamic and
static cache?
Ans) Dynamic Cache is used for Slowly changing Diamensions and also for Updating the
Master Table.
ii) For Flatfiles we use
Static Cache
13) What
is Star Schema?
Ans) The
simplest form of data warehousing schema that consists fact tables and
diamentionals is called Star Schema.
14) What
is a Junk Dimension?
Ans) The
Junk Dimension is a Dimension that is formed by lumping smaller dimensions.
15) What
are the two types of mapping in Getting Started Wizard?
Ans) The
two types of mapping in Getting Started Wizard are:
i)
Slowly growing target mapping
ii)
Simple pass through mapping
16) What
are the ways in which a Relational Source Definition can be updated?
Ans) The two ways in which a relational source
definition can be updated are:
i)
Edit the definition
ii)
Re import the definition.
17) How
many types of transformations does the sorted input support?
Ans )The sorted input supports three types of
transformations so that it will increase the session performance. They are:
i)
Lookup Transformation
ii)
Aggregator Transformation
iii)
Joiner Transformation
18) What
is a Snowflake Schema?
Ans) Fact table
that is connected to a number of dimension tables is called a Snowflake Schema.
19)
Why are the Star and the Snowflake schemes used?
Ans) The Star and the Snowflake schemas are the
methods used to store data which are multidimensional in nature.
20)
Name the databases that the Informatica server
can connect to on UNIX?
Ans i)
Oracle
iii)
DB2
iv)
Informix
v)
Sybas 0
vi)
Teradata
21)
How can we store the logs of a previous session?
Ans) When we run the Session in a timestamp mode then
the session log will not overwrite the current session logs.
22)
How many sessions can be created in a batch?
A)
Any number of sessions can be created in a
batch. But it is better to have less number of tasks so that it will easy
during the migration.
23)
What is a Surrogate key?
A)
The substitution for a Natural Primary Key is
called a Surrogate Key. It is a number or a Unique identifier of each row that
can be used as the primary key to the table.
24)
What is Staging area?
A)
The area where the data from different source
systems are brought together is called staging area. This Database act as an
input to Data Cleansing.
25)
Why do we use Target Designer?
A)
To create a Target Definition we use Target Designer.
26)
What is Metadata?
A)
Metadata describes the entity and attributes
description. Metadata can be defined as the Data about Data.
27)
Why do we use sql override in Informatica?
A)
To improve the performance e of lookup
transformations we use sql override in informatica.
28)
How do we create transformations?
A)
The tools used for creating Transformations are:
i)
Mapping Designer
ii)
Transformation Developer
iii)
Mapplet Designer
29)
What are the Output files that an Informatica server
creates during a session run?
A)
The output files created during session run are:
i)
Session Log
ii)
Workflow Log
iii)
Error Log
iv)
Badfile
30)
What is Data Mining?
A)
The process of analyzing the data from different
perspectives and summarizing it into useful information is called Data Mining.
31)
Difference between Abort and Stop?
A)
Abort command has a timeout of 60 seconds for
the server to complete the dtm process if it doesn’t finish by then it will
kill the dtm process.
Stop command does not have any time out
period; it immediately kills the reading process.
32)
How can we update a source definition?
A)
There are two ways in which we can update a
source definition:
i)
By editing the source definition
ii)
By reimporting the source definition
33)
How many types of threads are there in a dtm
process?
A)
There are 5 types of threads in dtm process:
i)
Mapping Thread
ii)
Reader Thread
iii)
Master Thread
iv)
Pre and post session thread
v)
Writer Thread
34)
What is a Power Analyzer in Informatica?
A) The Power Analyzer is a tool in Informatica
which gives advantages for data delivering, adhoc reporting and dashboard.This is the only BI tool
in Informatica.
35)
What is a fact table?
A)
The fact table is a main table or the central table that
contains the measures or facts of a business.
36)
What is a grain?
A)
Representation of data in different atomic levels in a
fact table is called a Grain. Granularity is an important factor in designing a
fact table.
37)
What are the different types of variables used in
informatica?
A)
The types of variables in informatica are:
i)
$ - Predefined variables
ii)
$$ - User defined variables
iii)
$$$ - System variables
38)
Define Tracing level. Name the different types of tracing
levels.
A)
The amount of information stored by an informatica server
in the log files is called tracing level.
The different types of tracing levels are:
i)
Normal
ii)
Terse
iii)
Verbose init
iv)
Verbose data
39)
What is the difference between Connected and Unconnected
Transformation?
A)
A connected transformation is directly connected to the
target table in the mapping or to other transformations whereas an unconnected
transformation is not connected to any other transformations in the mapping, it
is called with another transformation and returns a value to that
transformation.
40)
What are
the types of data that passes between informatica server and stored procedure?
A) There are 3 types of data in informatica:
i) Input / Output parameters
ii) Return Values
iii) Status code
A) There are 3 types of data in informatica:
i) Input / Output parameters
ii) Return Values
iii) Status code
41)
What are the different types of dimensions in
Informatica?
A)
The different types of dimensions are:
i)
Conformed Dimensions
ii)
Degenerative Dimensions
iii)
Junk Dimensions
42)
What is Degenerative Dimension?
A)
The dimension that is derived from the fact table and
does not have a dimension table of its own is called Degenerative Dimension.
43)
What is requirement Gathering?
A)
Requirement Gathering is nothing but interacting with end
users to know their requirements. Based on this the other faces of the project
are carried out. The other phases include analysis, Design, Implementation,
testing and maintenance. Requirement Gathering is done by a business analyst.
44)
Why do we use Shared Objects?
A)
If an object is shared by many users in a company. If we
have to update the object it would be easy if it is a shared object as the
object is automatically updated to all the users.
45)
What is Operational Data Store (ODS)?
A)
ODS is a hybrid data architecture which covers the
requirement of both analytical and operational tasks.
46)
What are the Meta data of source
that we import while importing the relational source definition from database?
A)
The meta data imported imported are;
i)
Database location
ii)
Source name
iii)
Column names
iv)
Data Types
v)
Key constraints
47)
What are the features of Complex Mapping?
A)
The features of complex mapping are:
i)
Difficult requirements
ii)
Many number of transformations
iii)
Complex business logic
48) What is standalone command task?
A) This Standalone
command task can be used anywhere in the workflow to run the shell command.
49) What is a
worklet in informatica ?
A) When all the
workflow tasks are grouped together it is called a worklet. Workflow tasks
include timer, decision, command, event wait, mail, session, link, assignment,
control etc.
50) What are the basic needs to join two sources in a source qualifier?
A)
Two sources can be joined if:
i)
Primary and foreign key relationships.
ii)
Matching data types.
51) What is the difference
between sets and batches?
A) A session is
a set of commands that describe the server to move data to the target whereas a
batch is a set of tasks that include one or more sessions or emails or commands
etc.
52) What is a
command task?
A) The command
task permits one or more than one shell commands in UNIX or DOS in windows to
run during the workflow.
53) What are the options in the target session of update strategy
transformation?
A) The different
options in a target session are:
i)
Insert
ii)
Delete
iii)
Update
iv)
Update as update
v)
Update as insert
vi)
Update else insert
vii)
Truncate table
54) What r two types of processes that informatica runs the session?
A) Load manager
Process: Starts the session, creates the DTM process, and sends post-session
email when the session completes.
The DTM process: Creates threads to initialize the session, read, write, and transform data, and handle pre- and post-session operations.
The DTM process: Creates threads to initialize the session, read, write, and transform data, and handle pre- and post-session operations.
55) In informatica where do we find
the throughput option?
A) Throughput
option in informatica can be found in workflow monitor. In workflow monitor,
right click on session, then click on get run properties and under
source/target statistics we can find throughput option.
56) Explain the use of aggregator cache file?
A) Aggregator
transformations are handled in chunks of instructions during each run. It
stores transitional values which are found in local buffer memory. Aggregators
provide extra cache files for storing the transformation values if extra memory
is required.
57) What are the
different types of batches?
A) There are two
types of batches:
i)
Sequential Batch: In this the sessions are run one after the other
ii)
Concurrent Batch: In this all the sessions are run at the same
time.
58) Name the
different types of fact tables.
A) There are
three types of Fact tables:
i)
Additive fact tables
ii)
Semi additive fact tables
iii)
Non additive fact tables.
59) Define a
Transformation?
A) A
transformation is a repository object that generates, modifies or passes data.
The designer provides a set of transformations that perform specific functions.
60) List out the
different types of transformations?
A) List of
transformations:
i)
Aggregator Transformation
ii)
Expression Transformation
iii)
Joiner Transformation
iv)
Filter Transformation
v)
Router Transformation
vi)
Rank Transformation
vii)
Stored Procedure Transformation
viii)
Update Strategy Transformation
ix)
Sorter Transformation
x)
Normalizer Transformation
xi)
Sequence Generator Transformation
xii)
XML source Qualifier Transformation
xiii)
Advanced external procedure Transformation
xiv)
External Transformation
xv)
Lookup Transformation
