Interview Questionary Set 4

76. How do you assign values from one session to another session?
1. Create workflow variable

2. Once the first session succeeded, use “Post-session on success variable assignment” to value to the workflow variable

3. In the second session, use “Pre-session variable assignment” re-assign workflow variable to session.

 

77. I want to run the second session after running first session 3 times?

1. Create Workflow variable Name: $$Session_Counter, Datatype: Integer, Persistent: Checked.

2. Create Assignment task and Place it in between the two session.

3. Edit “Assignment Task” à Expression Tab

Add follow expression:

IIF($$Session_Counter = 3, 1,  $$Session_Counter + 1 )

78. How do you override default lookup order by?

We can override default lookup order by clause, by place two dashes ‘--' as a comment notation after the ORDER BY clause to suppress the ORDER BY clause that the Integration Service generates.

79. What happen if one of the source qualifier port not linked with source instance?

The Integration Service through an internal error. The Source Qualifier contains an unbounded field [LOC].

80. What is difference between TRUE and FALSE in filter transformation?

A filter condition it returns TRUE or FALSE for each row that the Integration Service evaluates, depending on whether a row meets the specified condition.

·         For each row that returns TRUE, the Integration Services pass through the transformation.

·         For each row that returns FALSE, the Integration Service drops and writes a message to the session log.

81. Can We Use Source and Target objects inside Mapplets?

We can use Source objects inside the mapplets, but we cannot use Target objects inside the mapplets.

82. Explain the User Defined Functions in Informatica?

The User-defined functions extend the PowerCenter transformation language. We can create and manage user-defined functions with the PowerCenter transformation language in the Designer. We can add them to expressions in the Designer or Workflow Manger to reuse expression logic and build complex expressions. User-defined functions are available to other users in a repository.

83. What is pmcmd command and why we use it?

pmcmd is a program you use to communicate with the Integration Service. With pmcmd, we can perform some of the tasks that you can also perform in the Workflow Manager, such as starting and stopping workflows and sessions.

84. How you run workflow or session using command?

Command to run Workflow:
pmcmd startworkflow -sv IntService -d Domain -u user -p password -f Practice wf_s_m_sample

Command to run Session:

pmcmd starttask -sv IntService -d Domain -u user -p password -f Practice –w wf_s_sample s_m_sample

85. How many ways you can run a workflow or session or task?

We can run a workflow or session or task in 2 ways, Command line mode or Interactive mode.

86. What is use of code page?

A code page contains encoding to specify characters in a set of one or more languages. The code page is selected based on source of the dat. For example if source contains Japanese text then the code page should be selected to support Japanese text.

When a code page is chosen, the program or application for which the code page is set, refers to a specific set of data that describes the characters the application recognizes. This influences the way that application stores, receives, and sends character data.

87. What is a surrogate key?

A surrogate key is a substitution for the natural primary key. It is a unique identifier or number for each record of a dimension table that can be used for the primary key to the table instead of a "real" or natural key.

88. What is difference between Mapplet and reusable transformation?

Mapplet: A mapplet is set of transformation, which is created in Mapplet Designer based on some business logic. This can be re-used more than one mapping or across the other folder if it is created in shared folder.
Reusable Transformation: It is a single transformation having some business logic, which is created in Transformation Developer. This can be reused more than one mapplet or mapping or across the other folder if it is created in shared folder.

89. What is lookup function and how do you call it?

Lookup function is nothing, but searching for a value in a lookup source columns. The lookup function compares data in a lookup source to a value we specify. When the Integration Service finds the search value in the lookup table, it returns the value from a specified column in the same row in the lookup table.

Example:

syntax: lookup(result, search1, value1, search2, value2) where result is output, search is output and value is input.

LOOKUP(:TD.EMP.HIREDATE, :TD.EMP.EMPID, 112233, :TD.EMP.DEPTNO, 10)       

Note:

·         This Lookup function is used in expression transformation instead of un-connected lookup or uncached lookup.

·         NULL if the search does not find any matching values.

·         Error if the search finds more than one matching value.

90. What is the difference between truncate and delete options in the session?

The truncate option is used to truncate data from that table.
The Delete option is used to delete the records from table, which are flagged for deletion in update strategy.

91. What is Forward Rejected Rows?

The Forward Rejected Rows option is used to either pass rejected rows to next transformation or drop them. By default the Integration Service forward rejected rows to next transformation. The Integration Service flags the rows for reject and writes them to the session log file and passes to reject file. If you do not select Forward Rejected Rows option the Integration Service drops rejected rows and writes them to the session log file.

92. Under what condition selecting Sorted Input in aggregator may fail the session?

If the un-sorted data is passed to the aggregator and sorted input option is check then the session get failed.

93. What are the difference between joiner transformation and source qualifier transformation?

The Source Qualifier transformation is used to join source data from the relation source residing in the same schema, database or system.
The Joiner transformation is used to join source data from two related heterogeneous sources residing in different locations or file systems. You can also join data from the same source.

94. What are two types of processes that run the session?

The two types of processes that runs the session are Load Manager and DTM process.

• Load manager process starts the session, creates DTM process, and sends post session email when the session completes.
• DTM process creates threads to initialize the session, read, write and transform data and handle pre-session and post-session operations.

95. What are the Update Strategy transformation Constant and its values?
The Update Strategy transformation Constant are Insert, Update, Delete and Reject.

Operation	Constant	Numeric Value
Insert	DD_INSERT	0
Update	DD_UPDATE	1
Delete	DD_DELETE	2
Reject	DD_REJECT	3

96. What is a shared folder?

A shared folder is global or local folder where we can create objects like Source, Target, Transformation, Reusable Transformation, Mapplet, Mapping, Session, Workflow and Workflow. After create any object in shared folder that can be used in any other folder within the repository as shortcut object.

Any time if you made any modification to the object in the shared folder that will automatically reflect in the other folders.

97. What is a worklet and its uses?

A worklet is an object which represents a set of tasks created for reuse a set of business logic is called worklet. And which can be used more than one workflow within the folder.

98. What is file list and why it is used?

It contains list of files names and the files path which having same definition or structure, when you specify the source file type as “Indirect” then Integration Service read the data from the file list when we run the session.

99. What is Session and Batches?

Session: A Session is a set of instructions that tells to the Integration Service, how and when to move data from source to target.
Batch: A group by session is called as Batch

100. What are slowly changing dimensions?
Over a time period data would get changes, where if you want to maintain history for those changes, that process of maintaining history is called Slowly Changing Dimension.