What is the difference between PowerCenter and PowerMart?
With PowerCenter, you receive all product functionality, including the ability to register multiple servers, share metadata across repositories, and partition data.
A PowerCenter license lets you create a single repository that you can configure as a global repository, the core component of a data warehouse.
PowerMart includes all features except distributed metadata, multiple registered servers, and data partitioning. Also, the various options available with PowerCenter (such as PowerCenter Integration Server for BW, PowerConnect for IBM DB2, PowerConnect for IBM MQSeries, PowerConnect for SAP R/3, PowerConnect for Siebel, and PowerConnect for PeopleSoft) are not available with PowerMart.
What are the new features and enhancements in PowerCenter 5.1?
The major features and enhancements to PowerCenter 5.1 are:
a) Performance Enhancements
? High precision decimal arithmetic. The Informatica Server optimizes data throughput to increase performance of sessions using the Enable Decimal Arithmetic option.
? To_Decimal and Aggregate functions. The Informatica Server uses improved algorithms to increase performance of To_Decimal and all aggregate functions such as percentile, median, and average.
? Cache management. The Informatica Server uses better cache management to increase performance of Aggregator, Joiner, Lookup, and Rank transformations.
? Partition sessions with sorted aggregation. You can partition sessions with Aggregator transformation that use sorted input. This improves memory usage and increases performance of sessions that have sorted data.
b) Relaxed Data Code Page Validation
When enabled, the Informatica Client and Informatica Server lift code page selection and validation restrictions. You can select any supported code page for source, target, lookup, and stored procedure data.
c) Designer Features and Enhancements
? Debug mapplets. You can debug a mapplet within a mapping in the Mapping Designer. You can set breakpoints in transformations in the mapplet.
? Support for slash character (/) in table and field names. You can use the Designer to import source and target definitions with table and field names containing the slash character (/). This allows you to import SAP BW source definitions by connecting directly to the underlying database tables.
d) Server Manager Features and Enhancements
? Continuous sessions. You can schedule a session to run continuously. A continuous session starts automatically when the Load Manager starts. When the session stops, it restarts immediately without rescheduling. Use continuous sessions when reading real time sources, such as IBM MQSeries.
? Partition sessions with sorted aggregators. You can partition sessions with sorted aggregators in a mapping.
? Register multiple servers against a local repository. You can register multiple PowerCenter Servers against a local repository.
What is a repository?
The Informatica repository is a relational database that stores information, or metadata, used by the Informatica Server and Client tools. The repository also stores administrative information such as usernames and passwords, permissions and privileges, and product version.
We create and maintain the repository with the Repository Manager client tool. With the Repository Manager, we can also create folders to organize metadata and groups to organize users.
What are different kinds of repository objects? And what it will contain?
Repository objects displayed in the Navigator can include sources, targets, transformations, mappings, mapplets, shortcuts, sessions, batches, and session logs.
What are different kinds of repository objects? And what it will contain?
Repository objects displayed in the Navigator can include sources, targets, transformations, mappings, mapplets, shortcuts, sessions, batches, and session logs.
What is Sequence Generator Transformation?
The Sequence Generator transformation generates numeric values. We can use the Sequence Generator to create unique primary key values, replace missing primary keys, or cycle through a sequential range of numbers.
The Sequence Generation transformation is a connected transformation. It contains two output ports that we can connect to one or more transformations.
What is the difference between connected lookup and unconnected lookup?
Differences between Connected and Unconnected Lookups:
Connected Lookup Unconnected Lookup
Receives input values directly from the pipeline. Receives input values from the result of a :LKP expression in another transformation.
We can use a dynamic or static cache We can use a static cache
Supports user-defined default values Does not support user-defined default values
What are connected and unconnected Lookup transformations?
We can configure a connected Lookup transformation to receive input directly from the mapping pipeline, or we can configure an unconnected Lookup transformation to receive input from the result of an expression in another transformation.
An unconnected Lookup transformation exists separate from the pipeline in the mapping. We write an expression using the :LKP reference qualifier to call the lookup within another transformation.
A common use for unconnected Lookup transformations is to update slowly changing dimension tables.
What is a Lookup transformation and what are its uses?
We use a Lookup transformation in our mapping to look up data in a relational table, view or synonym.
We can use the Lookup transformation for the following purposes:
 Get a related value. For example, if our source table includes employee ID, but we want to include the employee name in our target table to make our summary data easier to read.
 Perform a calculation. Many normalized tables include values used in a calculation, such as gross sales per invoice or sales tax, but not the calculated value (such as net sales).
 Update slowly changing dimension tables. We can use a Lookup transformation to determine whether records already exist in the target.
What is a lookup table?
The lookup table can be a single table, or we can join multiple tables in the same database using a lookup query override. The Informatica Server queries the lookup table or an in-memory cache of the table for all incoming rows into the Lookup transformation.
If your mapping includes heterogeneous joins, we can use any of the mapping sources or mapping targets as the lookup table.
Where do you define update strategy?
We can set the Update strategy at two different levels:
? Within a session. When you configure a session, you can instruct the Informatica Server to either treat all records in the same way (for example, treat all records as inserts), or use instructions coded into the session mapping to flag records for different database operations.
? Within a mapping. Within a mapping, you use the Update Strategy transformation to flag records for insert, delete, update, or reject.
What is Update Strategy?
When we design our data warehouse, we need to decide what type of information to store in targets. As part of our target table design, we need to determine whether to maintain all the historic data or just the most recent changes.
The model we choose constitutes our update strategy, how to handle changes to existing records.
Update strategy flags a record for update, insert, delete, or reject. We use this transformation when we want to exert fine control over updates to a target, based on some condition we apply. For example, we might use the Update Strategy transformation to flag all customer records for update when the mailing address has changed, or flag all employee records for reject for people no longer working for the company.
What are the different types of Transformations?
a) Aggregator transformation: The Aggregator transformation allows you to perform aggregate calculations, such as averages and sums. The Aggregator transformation is unlike the Expression transformation, in that you can use the Aggregator transformation to perform calculations on groups. The Expression transformation permits you to perform calculations on a row-by-row basis only. (Mascot)
b) Expression transformation: You can use the Expression transformations to calculate values in a single row before you write to the target. For example, you might need to adjust employee salaries, concatenate first and last names, or convert strings to numbers. You can use the Expression transformation to perform any non-aggregate calculations. You can also use the Expression transformation to test conditional statements before you output the results to target tables or other transformations.
c) Filter transformation: The Filter transformation provides the means for filtering rows in a mapping. You pass all the rows from a source transformation through the Filter transformation, and then enter a filter condition for the transformation. All ports in a Filter transformation are input/output, and only rows that meet the condition pass through the Filter transformation.
d) Joiner transformation: While a Source Qualifier transformation can join data originating from a common source database, the Joiner transformation joins two related heterogeneous sources residing in different locations or file systems.
e) Lookup transformation: Use a Lookup transformation in your mapping to look up data in a relational table, view, or synonym. Import a lookup definition from any relational database to which both the Informatica Client and Server can connect. You can use multiple Lookup transformations in a mapping.
The Informatica Server queries the lookup table based on the lookup ports in the transformation. It compares Lookup transformation port values to lookup table column values based on the lookup condition. Use the result of the lookup to pass to other transformations and the target.
What is a transformation?
A transformation is a repository object that generates, modifies, or passes data. You configure logic in a transformation that the Informatica Server uses to transform data. The Designer provides a set of transformations that perform specific functions. For example, an Aggregator transformation performs calculations on groups of data.
Each transformation has rules for configuring and connecting in a mapping. For more information about working with a specific transformation, refer to the chapter in this book that discusses that particular transformation.
You can create transformations to use once in a mapping, or you can create reusable transformations to use in multiple mappings.
What are the tools provided by Designer?
The Designer provides the following tools:
? Source Analyzer. Use to import or create source definitions for flat file, XML, Cobol, ERP, and relational sources.
? Warehouse Designer. Use to import or create target definitions.
? Transformation Developer. Use to create reusable transformations.
? Mapplet Designer. Use to create mapplets.
? Mapping Designer. Use to create mappings.
What are the different types of Commit intervals?
The different commit intervals are:
? Target-based commit. The Informatica 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. The Informatica Server commits data based on the number of source rows. The commit point is the commit interval you configure in the session properties.
What is Event-Based Scheduling?
When you use event-based scheduling, the Informatica Server starts a session when it locates the specified indicator file. To use event-based scheduling, you need a shell command, script, or batch file to create an indicator file when all sources are available. The file must be created or sent to a directory local to the Informatica Server. The file can be of any format recognized by the Informatica Server operating system. The Informatica Server deletes the indicator file once the session starts.
Use the following syntax to ping the Informatica Server on a UNIX system:
pmcmd ping [{user_name | %user_env_var} {password | %password_env_var}] [hostname:]portno
Use the following syntax to start a session or batch on a UNIX system:
pmcmd start {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno [folder_name:]{session_name | batch_name} [:pf=param_file] session_flag wait_flag
Use the following syntax to stop a session or batch on a UNIX system:
pmcmd stop {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno[folder_name:]{session_name | batch_name} session_flag
Use the following syntax to stop the Informatica Server on a UNIX system:
pmcmd stopserver {user_name | %user_env_var} {password | %password_env_var} [hostname:]portno
I have the Administer Repository Privilege, but I cannot access a repository using the Repository Manager.
To perform administration tasks in the Repository Manager with the Administer Repository privilege, you must also have the default privilege Browse Repository. You can assign Browse Repository directly to a user login, or you can inherit Browse Repository from a group.
My privileges indicate I should be able to edit objects in the repository, but I cannot edit any metadata.
You may be working in a folder with restrictive permissions. Check the folder permissions to see if you belong to a group whose privileges are restricted by the folder owner.
How does read permission affect the use of the command line program, pmcmd?
To use pmcmd, you do not need to view a folder before starting a session or batch within the folder. Therefore, you do not need read permission to start sessions or batches with pmcmd. You must, however, know the exact name of the session or batch and the folder in which it exists.
With pmcmd, you can start any session or batch in the repository if you have the Session Operator privilege or execute permission on the folder.
I do not want a user group to create or edit sessions and batches, but I need them to access the Server Manager to stop the Informatica Server.
To permit a user to access the Server Manager to stop the Informatica Server, you must grant them both the Create Sessions and Batches, and Administer Server privileges. To restrict the user from creating or editing sessions and batches, you must restrict the user's write permissions on a folder level.
Alternatively, the user can use pmcmd to stop the Informatica Server with the Administer Server privilege alone.
I created a new group and removed the Browse Repository privilege from the group. Why does every user in the group still have that privilege? |
Privileges granted to individual users take precedence over any group restrictions. Browse Repository is a default privilege granted to all new users and groups. Therefore, to remove the privilege from users in a group, you must remove the privilege from the group, and every user in the group.
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