Informatica Transformations Explained (Part 1)

Aggregator Transformation

Aggregator transformation performs aggregate functions like average, sum, count etc. on multiple rows or groups. The Integration Service performs these calculations as it reads and stores data group and row data in an aggregate cache. It is an Active & Connected transformation.

Difference b/w Aggregator and Expression Transformation? Expression transformation permits you to perform calculations row by row basis only. In Aggregator you can perform calculations on groups.

Aggregator transformation has following ports – State, State_Count, Previous_State and State_Counter.

Components: Aggregate Cache, Aggregate Expression, Group by port, Sorted input.

Aggregate Expressions: are allowed only in aggregate transformations. can include conditional clauses and non-aggregate functions. can also include one aggregate function nested into another aggregate function.

Aggregate Functions: AVG, COUNT, FIRST, LAST, MAX, MEDIAN, MIN, PERCENTILE, STDDEV, SUM, VARIANCE

Application Source Qualifier Transformation

Represents the rows that the Integration Service reads from an application, such as an ERP source, when it runs a session.It is an Active & Connected transformation.

Custom Transformation

It works with procedures you create outside the designer interface to extend PowerCenter functionality. calls a procedure from a shared library or DLL. It is active/passive & connected type.

You can use CT to create T. that require multiple input groups and multiple output groups.

Custom transformation allows you to develop the transformation logic in a procedure. Some of the PowerCenter transformations are built using the Custom transformation. Rules that apply to Custom transformations, such as blocking rules, also apply to transformations built using Custom transformations. PowerCenter provides two sets of functions called generated and API functions. The Integration Service uses generated functions to interface with the procedure. When you create a Custom transformation and generate the source code files, the Designer includes the generated functions in the files. Use the API functions in the procedure code to develop the transformation logic.

Difference between Custom and External Procedure Transformation? In Custom T, input and output functions occur separately.The Integration Service passes the input data to the procedure using an input function. The output function is a separate function that you must enter in the procedure code to pass output data to the Integration Service. In contrast, in the External Procedure transformation, an external procedure function does both input and output, and its parameters consist of all the ports of the transformation.

Data Masking Transformation

Passive & Connected. It is used to change sensitive production data to realistic test data for non production environments. It creates masked data for development, testing, training and data mining. Data relationship and referential integrity are maintained in the masked data.

Example: It returns masked value that has a realistic format for SSN, Credit card number, birthdate, phone number, etc. But is not a valid value.

Masking types: Key Masking, Random Masking, Expression Masking, Special Mask format. Default is no masking.

Expression Transformation

Passive & Connected. are used to perform non-aggregate functions, i.e to calculate values in a single row. Example: to calculate discount of each product or to concatenate first and last names or to convert date to a string field.

You can create an Expression transformation in the Transformation Developer or the Mapping Designer.

Components: Transformation, Ports, Properties, Metadata Extensions.

External Procedure

Passive & Connected or Unconnected. It works with procedures you create outside of the Designer interface to extend PowerCenter functionality. You can create complex functions within a DLL or in the COM layer of windows and bind it to external procedure transformation. To get this kind of extensibility, use the Transformation Exchange (TX) dynamic invocation interface built into PowerCenter. You must be an experienced programmer to use TX and use multi-threaded code in external procedures.

Filter Transformation

Active & Connected. It allows rows that meet the specified filter condition and removes the rows that do not meet the condition. For example, to find all the employees who are working in NewYork or to find out all the faculty member teaching Chemistry in a state. The input ports for the filter must come from a single transformation. You cannot concatenate ports from more than one transformation into the Filter transformation.

Components: Transformation, Ports, Properties, Metadata Extensions.

HTTP Transformation

Passive & Connected. It allows you to connect to an HTTP server to use its services and applications. With an HTTP transformation, the Integration Service connects to the HTTP server, and issues a request to retrieves data or posts data to the target or downstream transformation in the mapping.

Authentication types: Basic, Digest and NTLM.

Examples: GET, POST and SIMPLE POST.

Java Transformation

Active or Passive & Connected. It provides a simple native programming interface to define transformation functionality with the Java programming language. You can use the Java transformation to quickly define simple or moderately complex transformation functionality without advanced knowledge of the Java programming language or an external Java development environment.

Joiner Transformation

Active & Connected. It is used to join data from two related heterogeneous sources residing in different locations or to join data from the same source. In order to join two sources, there must be at least one or more pairs of matching column between the sources and a must to specify one source as master and the other as detail. For example: to join a flat file and a relational source or to join two flat files or to join a relational source and a XML source.

The Joiner transformation supports the following types of joins:

  • Normal: Normal join discards all the rows of data from the master and detail source that do not match, based on the condition.
  • Master Outer: Master outer join discards all the unmatched rows from the master source and keeps all the rows from the detail source and the matching rows from the master source.
  • Detail Outer: Detail outer join keeps all rows of data from the master source and the matching rows from the detail source. It discards the unmatched rows from the detail source.
  • Full Outer: Full outer join keeps all rows of data from both the master and detail sources.

Limitations on the pipelines you connect to the Joiner transformation:
*You cannot use a Joiner transformation when either input pipeline contains an Update Strategy transformation.
*You cannot use a Joiner transformation if you connect a Sequence Generator transformation directly before the Joiner transformation.

Lookup Transformation

Passive & Connected or UnConnected. It is used to look up data in a flat file, relational table, view, or synonym. It compares lookup transformation ports (input ports) to the source column values based on the lookup condition. Later returned values can be passed to other transformations. You can create a lookup definition from a source qualifier and can also use multiple Lookup transformations in a mapping.

You can perform the following tasks with a Lookup transformation:
*Get a related value. Retrieve a value from the lookup table based on a value in the source. For example, the source has an employee ID. Retrieve the employee name from the lookup table.
*Perform a calculation. Retrieve a value from a lookup table and use it in a calculation. For example, retrieve a sales tax percentage, calculate a tax, and return the tax to a target.
*Update slowly changing dimension tables. Determine whether rows exist in a target.

Lookup Components: Lookup source, Ports, Properties, Condition.

Types of Lookup:

  1. Relational or flat file lookup.
  2. Pipeline lookup.
  3. Cached or uncached lookup.
  4. connected or unconnected lookup.

 

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