Informatica Scenario Based Interview Question and Answers

Informatica Scenario Based Interview Questions with Answers:

1.How to generate sequence number using expression transformation
Solution:
In the expression transformation, create a variable port and increment it by 1. Then assign the
variable port to an output port. In the expression transformation, the ports are:
V_count=V_count+1
O_count=V_count

2. Design a mapping to load the first 3 rows from a flat file into a target?
Solution:
You have to assign row numbers to each record. Generate the row numbers either using the
expression transformation as mentioned above or use sequence generator transformation.
Then pass the output to filter transformation and specify the filter condition as O_count <=3


3. Design a mapping to load the last 3 rows from a flat file into a target?
Solution:
Consider the source has the following data.
col
a
b
c
d
e
Step1: You have to assign row numbers to each record. Generate the row numbers using the
expression transformation as mentioned above and call the row number generated port as O_count.
Create a DUMMY output port in the same expression transformation and assign 1 to that port. So
that, the DUMMY output port always return 1 for each row.
In the expression transformation, the ports are
V_count=V_count+1
O_count=V_count
O_dummy=1
The output of expression transformation will be
col, o_count, o_dummy
a, 1, 1
b, 2, 1
c, 3, 1
d, 4, 1
e, 5, 1
Step2: Pass the output of expression transformation to aggregator and do not specify any group by
condition. Create an output port O_total_records in the aggregator and assign O_count port to it.
The aggregator will return the last row by default. The output of aggregator contains the DUMMY
port which has value 1 and O_total_records port which has the value of total number of records in
the source.
In the aggregator transformation, the ports are
O_dummy
O_count
O_total_records=O_count
The output of aggregator transformation will be
O_total_records, O_dummy
5, 1
Step3: Pass the output of expression transformation, aggregator transformation to
joiner transformation and join on the DUMMY port. In the joiner transformation check the property
sorted input, then only you can connect both expression and aggregator to joinertransformation.
In the joiner transformation, the join condition will be
O_dummy (port from aggregator transformation) = O_dummy (port fromexpressiontransformation)
The output of joiner transformation will be
col, o_count, o_total_records
a, 1, 5
b, 2, 5
c, 3, 5
d, 4, 5
e, 5, 5
Step4: Now pass the ouput of joiner transformation to filter transformation and specify the filter
condition as O_total_records (port from aggregator)-O_count(port from expression) <=2
In the filter transformation, the filter condition will be
O_total_records – O_count <=2
The output of filter transformation will be
col o_count, o_total_records
c, 3, 5
d, 4, 5
e, 5, 5

4. Design a mapping to load the first record from a flat file into one table A, the last record from a
flat file into table B and the remaining records into table C?

Solution:
This is similar to the above problem; the first 3 steps are same. In the last step instead of using the
filter transformation, you have to use router transformation. In the router transformation create two
output groups.
In the first group, the condition should be O_count=1 and connect the corresponding output group
to table A. In the second group, the condition should be O_count=O_total_records and connect the
corresponding output group to table B. The output of default group should be connected to table C.


5. Consider the following products data which contain duplicate rows.
A
B
C
C
B
D
B
Q1. Design a mapping to load all unique products in one table and the duplicate rows in another
table.
The first table should contain the following output
A
D
The second target should contain the following output
B
B
B
C
C
Solution:
Use sorter transformation and sort the products data. Pass the output to an
expressiontransformation and create a dummy port O_dummy and assign 1 to that port. So that, the
DUMMY output port always return 1 for each row.
The output of expression transformation will be
Product, O_dummy
A, 1
B, 1
B, 1
B, 1
C, 1
C, 1
D, 1
Pass the output of expression transformation to an aggregator transformation. Check the group byon product port. In the aggreagtor, create an output port O_count_of_each_product and write an
expression count(product).
The output of aggregator will be
Product, O_count_of_each_product
A, 1
B, 3
C, 2
D, 1
Now pass the output of expression transformation, aggregator transformation to
joinertransformation and join on the products port. In the joiner transformation check the property
sorted input, then only you can connect both expression and aggregator to joinertransformation.
The output of joiner will be
product, O_dummy, O_count_of_each_product
A, 1, 1
B, 1, 3
B, 1, 3
B, 1, 3
C, 1, 2
C, 1, 2
D, 1, 1
Now pass the output of joiner to a router transformation, create one group and specify the group
condition as O_dummy=O_count_of_each_product. Then connect this group to onetable. Connect
the output of default group to another table.

Q2. Design a mapping to load each product once into one table and the remaining products which
are duplicated into another table.

The first table should contain the following output
A
B
C
D
The second table should contain the following output
B
B
C
Solution:
Use sorter transformation and sort the products data. Pass the output to an
expression transformation and create a variable port,V_curr_product, and assign product port to it.
Then create a V_count port and in the expression editor write
IIF(V_curr_product=V_prev_product, V_count+1,1). Create one more variable port V_prev_port
and assign product port to it. Now create an output port O_count port and assign V_count port to
it.
In the expression transformation, the ports are
Product
V_curr_product=product
V_count=IIF(V_curr_product=V_prev_product,V_count+1,1)
V_prev_product=product
O_count=V_count
The output of expression transformation will be
Product, O_count
A, 1
B, 1
B, 2
B, 3
C, 1
C, 2
D, 1
Now Pass the output of expression transformation to a router transformation, create one group and
specify the condition as O_count=1. Then connect this group to one table. Connect the output of
default group to another table.
Informatica Scenario Based Questions1. Consider the following employees data as source
employee_id, salary
10, 1000
20, 2000
30, 3000
40, 5000

Q3. Design a mapping to load the cumulative sum of salaries of employees into
target table?

The target table data should look like as
employee_id, salary, cumulative_sum
10, 1000, 1000
20, 2000, 3000
30, 3000, 6000
40, 5000, 11000
Solution:
Connect the source Qualifier to expression transformation. In the
expression transformation, create a variable port V_cum_sal and in the expression editor
write V_cum_sal+salary. Create an output port O_cum_sal and assign V_cum_sal to it.
Q2. Design a mapping to get the pervious row salary for the current row. If there is no
pervious row exists for the current row, then the pervious row salary should be displayed
as null.
The output should look like as
employee_id, salary, pre_row_salary
10, 1000, Null
20, 2000, 1000
30, 3000, 2000
40, 5000, 3000
Solution:
Connect the source Qualifier to expression transformation. In the
expressiontransformation, create a variable port V_count and increment it by one for
each row entering the expression transformation. Also create V_salary variable port and
assign the expression IIF(V_count=1,NULL,V_prev_salary) to it . Then create one more
variable port V_prev_salary and assign Salary to it. Now create output port O_prev_salary
and assign V_salary to it. Connect the expression transformation to the target ports.
In the expression transformation, the ports will be
employee_id
salary
V_count=V_count+1
V_salary=IIF(V_count=1,NULL,V_prev_salary)
V_prev_salary=salary
O_prev_salary=V_salary


Q4. Design a mapping to find the sum of salaries of all employees and this sum should
repeat for all the rows
.
The output should look like as
employee_id, salary, salary_sum
10, 1000, 11000
20, 2000, 11000
30, 3000, 11000
40, 5000, 11000
Solution:
Step1: Connect the source qualifier to the expression transformation. In the
expressiontransformation, create a dummy port and assign value 1 to it.
In the expression transformation, the ports will be
employee_id
salary
O_dummy=1
Step2: Pass the output of expression transformation to aggregator. Create a new port
O_sum_salary and in the expression editor write SUM(salary). Do not specify group by on
any port.
In the aggregator transformation, the ports will be
salary
O_dummy
O_sum_salary=SUM(salary)
Step3: Pass the output of expression transformation, aggregator transformation to
joinertransformation and join on the DUMMY port. In the joiner transformation check
the property sorted input, then only you can connect both expression and aggregator to
joinertransformation.Step4: Pass the output of joiner to the target table.
2. Consider the following employees table as source
department_no, employee_name
20, R
10, A
10, D
20, P
10, B
10, C
20, Q
20, S
Q1. Design a mapping to load a target table with the following values from the above
source?
department_no, employee_list
10, A
10, A,B
10, A,B,C
10, A,B,C,D
20, A,B,C,D,P
20, A,B,C,D,P,Q
20, A,B,C,D,P,Q,R
20, A,B,C,D,P,Q,R,S
Solution:
Step1: Use a sorter transformation and sort the data using the sort key as
department_no and then pass the output to the expression transformation. In the
expressiontransformation, the ports will be
department_no
employee_name
V_employee_list =
IIF(ISNULL(V_employee_list),employee_name,V_employee_list||’,’||employee_name)
O_employee_list = V_employee_list
Step2: Now connect the expression transformation to a target table.


Q5. Design a mapping to load a target table with the following values from the above
source?

department_no, employee_list
10, A
10, A,B
10, A,B,C
10, A,B,C,D
20, P
20, P,Q
20, P,Q,R
20, P,Q,R,S
Solution:
Step1: Use a sorter transformation and sort the data using the sort key as
department_no and then pass the output to the expression transformation. In the
expressiontransformation, the ports will be
department_no
employee_name
V_curr_deptno=department_no
V_employee_list = IIF(V_curr_deptno! =V_prev_deptno,employee_name,V_employee_list||’,’||employee_name)
V_prev_deptno=department_no
O_employee_list = V_employee_list
Step2: Now connect the expression transformation to a target table.


Q6. Design a mapping to load a target table with the following values from the above
source?

department_no, employee_names
10, A,B,C,D
20, P,Q,R,S
Solution:
The first step is same as the above problem. Pass the output of expression to an
aggregator transformation and specify the group by as department_no. Now connect the
aggregator transformation to a target table.

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