Informatica Transformations Explained (Part 2)

Normalizer Transformation

Active & Connected. The Normalizer transformation processes multiple-occurring columns or multiple-occurring groups of columns in each source row and returns a row for each instance of the multiple-occurring data. It is used mainly with COBOL sources where most of the time data is stored in de-normalized format.

You can create following Normalizer transformation:
*VSAM Normalizer transformation. A non-reusable transformation that is a Source Qualifier transformation for a COBOL source. VSAM stands for Virtual Storage Access Method, a file access method for IBM mainframe.

*Pipeline Normalizer transformation. A transformation that processes multiple-occurring data from relational tables or flat files. This is default when you create a normalizer transformation.

Components: Transformation, Ports, Properties, Normalizer, Metadata Extensions.

Rank Transformation

Active & Connected. It is used to select the top or bottom rank of data. You can use it to return the largest or smallest numeric value in a port or group or to return the strings at the top or the bottom of a session sort order. For example, to select top 10 Regions where the sales volume was very high or to select 10 lowest priced products.

As an active transformation, it might change the number of rows passed through it. Like if you pass 100 rows to the Rank transformation, but select to rank only the top 10 rows, passing from the Rank transformation to another transformation.
You can connect ports from only one transformation to the Rank transformation. You can also create local variables and write non-aggregate expressions.

Router Transformation

Active & Connected. It is similar to filter transformation because both allow you to apply a condition to test data. The only difference is, filter transformation drops the data that do not meet the condition whereas router has an option to capture the data that do not meet the condition and route it to a default output group.

If you need to test the same input data based on multiple conditions, use a Router transformation in a mapping instead of creating multiple Filter transformations to perform the same task. The Router transformation is more efficient.

Sequence Generator Transformation

Passive & Connected transformation. It is used to create unique primary key values or cycle through a sequential range of numbers or to replace missing primary keys.

It has two output ports: NEXTVAL and CURRVAL. You cannot edit or delete these ports. Likewise, you cannot add ports to the transformation. NEXTVAL port generates a sequence of numbers by connecting it to a transformation or target. CURRVAL is the NEXTVAL value plus one or NEXTVAL plus the Increment By value.

You can make a Sequence Generator reusable, and use it in multiple mappings. You might reuse a Sequence Generator when you perform multiple loads to a single target.

For non-reusable Sequence Generator transformations, Number of Cached Values is set to zero by default, and the Integration Service does not cache values during the session.For non-reusable Sequence Generator transformations, setting Number of Cached Values greater than zero can increase the number of times the Integration Service accesses the repository during the session. It also causes sections of skipped values since unused cached values are discarded at the end of each session.

For reusable Sequence Generator transformations, you can reduce Number of Cached Values to minimize discarded values, however it must be greater than one. When you reduce the Number of Cached Values, you might increase the number of times the Integration Service accesses the repository to cache values during the session.

Sorter Transformation

Active & Connected transformation. It is used sort data either in ascending or descending order according to a specified sort key. You can also configure the Sorter transformation for case-sensitive sorting, and specify whether the output rows should be distinct. When you create a Sorter transformation in a mapping, you specify one or more ports as a sort key and configure each sort key port to sort in ascending or descending order.

Source Qualifier Transformation

Active & Connected transformation. When adding a relational or a flat file source definition to a mapping, you need to connect it to a Source Qualifier transformation. The Source Qualifier is used to join data originating from the same source database, filter rows when the Integration Service reads source data, Specify an outer join rather than the default inner join and to specify sorted ports.

It is also used to select only distinct values from the source and to create a custom query to issue a special SELECT statement for the Integration Service to read source data

SQL Transformation

Active/Passive & Connected transformation. The SQL transformation processes SQL queries midstream in a pipeline. You can insert, delete, update, and retrieve rows from a database. You can pass the database connection information to the SQL transformation as input data at run time. The transformation processes external SQL scripts or SQL queries that you create in an SQL editor. The SQL transformation processes the query and returns rows and database errors.

Stored Procedure Transformation

Passive & Connected or UnConnected transformation. It is useful to automate time-consuming tasks and it is also used in error handling, to drop and recreate indexes and to determine the space in database, a specialized calculation etc. The stored procedure must exist in the database before creating a Stored Procedure transformation, and the stored procedure can exist in a source, target, or any database with a valid connection to the Informatica Server. Stored Procedure is an executable script with SQL statements and control statements, user-defined variables and conditional statements.

Transaction Control Transformation

Active & Connected. You can control commit and roll back of transactions based on a set of rows that pass through a Transaction Control transformation. Transaction control can be defined within a mapping or within a session.
Components: Transformation, Ports, Properties, Metadata Extensions.

Union Transformation

Active & Connected. The Union transformation is a multiple input group transformation that you use to merge data from multiple pipelines or pipeline branches into one pipeline branch. It merges data from multiple sources similar to the UNION ALL SQL statement to combine the results from two or more SQL statements. Similar to the UNION ALL statement, the Union transformation does not remove duplicate rows.
Rules

  1. You can create multiple input groups, but only one output group.
  2. All input groups and the output group must have matching ports. The precision, datatype, and scale must be identical across all groups.
  3. The Union transformation does not remove duplicate rows. To remove duplicate rows, you must add another transformation such as a Router or Filter transformation.
  4. You cannot use a Sequence Generator or Update Strategy transformation upstream from a Union transformation.
  5. The Union transformation does not generate transactions.

Components: Transformation tab, Properties tab, Groups tab, Group Ports tab.

Unstructured Data Transformation

Active/Passive and connected. The Unstructured Data transformation is a transformation that processes unstructured and semi-structured file formats, such as messaging formats, HTML pages and PDF documents. It also transforms structured formats such as ACORD, HIPAA, HL7, EDI-X12, EDIFACT, AFP, and SWIFT.

Components: Transformation, Properties, UDT Settings, UDT Ports, Relational Hierarchy.

Update Strategy Transformation

Active & Connected transformation. It is used to update data in target table, either to maintain history of data or recent changes. It flags rows for insert, update, delete or reject within a mapping.

XML Generator Transformation

Active & Connected transformation. It lets you create XML inside a pipeline. The XML Generator transformation accepts data from multiple ports and writes XML through a single output port.

XML Parser Transformation

Active & Connected transformation. The XML Parser transformation lets you extract XML data from messaging systems, such as TIBCO or MQ Series, and from other sources, such as files or databases. The XML Parser transformation functionality is similar to the XML source functionality, except it parses the XML in the pipeline.

XML Source Qualifier Transformation

Active & Connected transformation. XML Source Qualifier is used only with an XML source definition. It represents the data elements that the Informatica Server reads when it executes a session with XML sources. has one input or output port for every column in the XML source.

External Procedure Transformation

Active & Connected/UnConnected transformation. Sometimes, the standard transformations such as Expression transformation may not provide the functionality that you want. In such cases External procedure is useful to develop complex functions within a dynamic link library (DLL) or UNIX shared library, instead of creating the necessary Expression transformations in a mapping.

Advanced External Procedure Transformation

Active & Connected transformation. It operates in conjunction with procedures, which are created outside of the Designer interface to extend PowerCenter/PowerMart functionality. It is useful in creating external transformation applications, such as sorting and aggregation, which require all input rows to be processed before emitting any output rows.

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