07/31/2017
31) can you connect more than one group to the same target or transformation?
NO
32) what is a reusable transformation?
Reusable transformation can be a single transformation.This transformation can be used in multiple mappings.when you need to incorporate this transformation into mapping you add an instance of it to mapping.Later if you change the definition of the transformation, all instances of it inherit the changes.Since the instance of reusable transformation is a pointer to that transformation.U can change the transformation in the transformation developer, its instance automatically reflect these changes. This feature can save U great deal of work.
-- what are the methods for creating reusable transformation?
Two methods
1) Design it in the transformation developer.
2) Promote a standard transformation from the mapping designer.After you add a transformation to the mapping, you can promote it to status of reusable transformation.
Once you promote a standard transformation to reusable status, you can demote it to a standard transformation at any time.
If u change the properties of a reusable transformation in mapping , you can revert it to the original reusable transformation properties by clicking the revert.
33) what are mapping parameters and mapping variables?
Mapping parameter represents a constant value that you can define before running a session.A mapping parameter retains the same value throughout the entire session.
When you use the mapping parameter , you declare and use the parameter in a mapping or mapplet.Then define the value of parameter in a parameter file for the session.
Unlike a mapping parameter, a mapping variable represents a value that can change through out the session. The informatica server save the value of mapping variable to the repository at the end of session run and uses that value next time you run the session.
34) can you use the mapping parameters or variables created in one mapping into another mapping?
NO, we can use mapping parameters or variables in any transformation of the same mapping or mapplet in which have crated mapping parameters or variables.
35) Can you are the mapping parameters or variables created in one mapping into any other result transformation.
Yes because the reusable transformation is not contained with any mapplet or mapping.
36) How the informatica server sorts the string values in rank transformation?
When the informatica server runs in the ASCII data movement mode it sorts session data using binary sort order.If you configures the session to use a binary sort order, the informatica server calculates the binary value of each string and returns the specified number of rows with the highest binary values for the string.
37) What is the rank index in rank transformation?
The designer automatically creates a RANKINDEX port for each Rank transformation. The informatica server uses the Rank Index port to store the ranking position for each record in a group.For example, if you create a Rank transformation that ranks the top 5 sales persons for each quarter, the rank index number the salespeople from 1 to 5.
38) what is the mapplet?
Mapplet is a set of transformation that you build in the mapplet designer and you can use in multiple mappings.
39) Difference between mapplet and reusable transformation?
Reusable transformation can be a single transformation.Where as mapplet use multiple transformations.
40) what is a parameter a file?
Paramater file defines the values for parameter and variables.
WORKFLOW MANAGER
41) what is a server?
The power center server moves data from source to targets based on a workflow and mapping metadata stored in a repository.
42) what is a work flow?
A workflow is a set of instructions that describe how and when to run tasks related to extracting,transformation and loading data.
-- what is session?
A session is a set of instructions that describes how to move data from source to target using a mapping.
-- what is workflow monitor?
Use the work flow monitor work flows and stop the power center server.
43) explain a work flow process?
The power center server uses both process memory and system shared memory to perform these tasks.
Load manager process: stores and locks the workflow tasks and start the DTM run the sessions.
Data Transformation Process DTM: Perform session validations,create threads to initialize the session,read,write and transform data, and handle pre and post session operations.
The default memory allocation is 12,000,000 bytes.
44) What are types of threads in DTM?
The main dtm thread is called the master thread.
Mapping thread.
Transformation thread.
Reader thread.
Writer thread.
Pre-and-post session thread.
45) Explain work flow manager tools?
1) Task developer.
2) Work flow designer.
3) Worklet designer.
46) Explain work flow schedule.
You can sehedule a work flow to run continuously, repeat at given time or interval or you manually start a work flow.By default the workflow runs on demand.
47) Explain stopping or aborting a session task?
If the power center is executing a session task when you issue the stop the command the power center stop reading data. If continuous processing and writing data and committing data to targets.
If the power center can’t finish processing and committing data you issue the abort command.
You can also abort a session by using the Abort() function in the mapping logic.
48) What is a worklet?
A worklet is an object that represents a set of taske.It can contain any task available in the work flow manager. You can run worklets inside a workflow. You can also nest a worklet in another worklet.The worklet manager does not provide a parameter file for worklets.
The power center server writes information about worklet ex*****on in the workflow log.
49) what is a commit interval and explain the types?
A commit interval is the interval at which power center server commits data to targets during a session. The commit interval the number of rows you want to use as a basis for the commit point.
Target Based commit: The power center server commits data based on the number of target rows and the key constraints on the target table. The commit point also depends on the buffer block size and the commit interval.
Source-based commit:---------------------------------------------
User-defined commit:----------------------------------------------
50) Explain bulk loading?
You can use bulk loading to improve performance of a session that inserts a large amount of data to a db2,sysbase,oracle or MS SQL server database.
When bulk loading the power center server by passes the database log,which speeds performance.
With out writing to the database log, however the target database can’t perform rollback.As a result you may not be perform recovery.
51) What is a constraint based loading?
When you select this option the power center server orders the target load on a row-by-row basis only.
Edit tasks->properties->select treat source rows as insert.
Edit tasks->config object tab->select constraint based
If session is configured constraint absed loading when target table receive rows from different sources.The power center server revert the normal loading for those tables but loads all other targets in the session using constraint based loading when possible loading the primary key table first then the foreign key table.
Use the constraint based loading only when the session option treat rows as set to insert.
Constraint based load ordering functionality which allows developers to read the source once and populate parent and child tables in a single process.
52) Explain incremental aggregation?
When using incremental aggregation you apply captured changes in the source to aggregate calculations in a session.If the source changes only incrementally and you can capture changes you can configure the session to process only those changes. This allows the power center server to update your target incrementally rather than forcing it to process the entire source and recalculate the same data each time you run the session.
You can capture new source data.use incremental aggregation when you can capture new source data much time you run the session.Use a stored procedure on filter transformation only new data.
Incremental changes do not significantly change the target.Use incremental aggregation when the changes do not significantly change the target.If processing the incrementally changed source alters more than half the existing target, the session may not benefit from using incremental aggregation. In this case drop the table and recreate the target with complete source data.
53) Processing of incremental aggregation
The first time u run an incremental aggregation session the power center server process the entire source.At the end of the session the power center server stores aggregate data from the session runs in two files, the index file and the data file .The power center server creates the files in a local directory.
Transformations.
--- what is transformation?
Transformation is repository object that generates modifies or passes data.
54) what are the type of transformations?
2 types:
1) active
2) passive.
-- explain active and passive transformation?
Active transformation can change the number of rows that pass through it.No of output rows less than or equal to no of input rows.
Passive transformation does not change the number of rows.Always no of output rows equal to no of input rows.
55) Difference filter and router transformation.
Filter transformation to filter the data only one condition and drop the rows don’t meet the condition.
Drop rows does not store any ware like session log file..
Router transformation to filter the data based on multiple conditions and give yiou the option to route rows that don’t match to a default group.
56) what r the types of groups in router transformation?
Router transformation 2 groups 1. Input group 2. output groups.
Output groups in 2 types. 1. user defined group 2. default group.
57) difference between expression and aggregator transformation?
Expression transformation calculate the single row values before writes the target.Expression transformation executed by row-by-row basis only.
Aggregator transformation allows you to perform aggregate calculations like max, min,avg…
Aggregate transformation perform calculation on groups.
58) How can u improve the session performance in aggregate transformation?
Use stored input.
59) what is aggregate cache in aggregate transformation?
The aggregate stores data in the aggregate cache until it completes aggregate calculations.When u run a session that uses an aggregate transformation , the informatica server creates index and data caches in memory is process the transformation. If the informatica server requires more space it seores overview values in cache files.
