What is the difference between mapping level and session level variables?

What is the difference between mapping level and session level variables?

Mapping level variables always starts with $$.

A session level variable always starts with $.

Flat File

Flat file is a collection of data in a file in the specific format.

Informatica can support two types of files

Delimiter

Fixed Width

In delimiter we need to specify the separator.

In fixed width we need to known about the format first. Means how many character to read for particular column.

In delimiter also it is necessary to know about the structure of the delimiter. Because to know about the headers.

If the file contains the header then in definition we need to skip the first row.

List file:

If you want to process multiple files with same structure. We don’t need multiple mapping and multiple sessions.

We can use one mapping one session using list file option.

First we need to create the list file for all the files. Then we can use this file in the main mapping.

System Variables:

$$$SessStartTime returns the initial system date value on the machine hosting the Integration Service when the server initializes a session. $$$SessStartTime returns the session start time as a string value. The format of the string depends on the database you are using.

Session: A session is a set of instructions that tells informatica Server how to move data from sources to targets.

WorkFlow: A workflow is a set of instructions that tells Informatica Server how to execute tasks such as sessions, email notifications and commands. In a workflow multiple sessions can be included to run in parallel or sequential manner.

Source Definition: The Source Definition is used to logically represent database table or Flat files.

Target Definition: The Target Definition is used to logically represent a database table or file in the Data Warehouse / Data Mart.

Aggregator: The Aggregator transformation is used to perform Aggregate calculations on group basis.

Expression: The Expression transformation is used to perform the arithmetic calculation on row by row basis and also used to convert string to integer vis and concatenate two columns.

Filter: The Filter transformation is used to filter the data based on single condition and pass through next transformation.

Router: The router transformation is used to route the data based on multiple conditions and pass through next transformations.

It has three groups

1) Input group

2) User defined group

3) Default group

Joiner: The Joiner transformation is used to join two sources residing in different databases or different locations like flat file and oracle sources or two relational tables existing in different databases.

Source Qualifier: The Source Qualifier transformation is used to describe in SQL the method by which data is to be retrieved from a source application system and also used to join two relational sources residing in same databases.

Mapping: Mapping is the Informatica Object which contains set of transformations including source and target. Its look like pipeline.

Mapplet: set of transformation

Mapplet is a set of reusable transformations. We can use this mapplet in any mapping within the Folder.

A mapplet can be active or passive depending on the transformations in the mapplet. Active mapplets contain one or more active transformations. Passive mapplets contain only passive transformations.

When you add transformations to a mapplet, keep the following restrictions in mind:

If you use a Sequence Generator transformation, you must use a reusable Sequence Generator transformation.

If you use a Stored Procedure transformation, you must configure the Stored Procedure Type to be Normal.

You cannot include the following objects in a mapplet:

Normalizer transformations

COBOL sources

XML Source Qualifier transformations

XML sources

Target definitions

Other mapplets

The mapplet contains Input transformations and/or source definitions with at least one port connected to a transformation in the mapplet.

The mapplet contains at least one Output transformation with at least one port connected to a transformation in the mapplet.

Input Transformation: Input transformations are used to create a logical interface to a mapplet in order to allow data to pass into the mapplet.

Output Transformation: Output transformations are used to create a logical interface from a mapplet in order to allow data to pass out of a mapplet.

Informatica is a powerful Extraction, Transformation, and Loading tool and is been deployed for data warehouse development in the Business Intelligence Team. Informatica comes with the following clients to perform various tasks.

·        Designer – used to develop transformations/mappings

·        Workflow Manager / Workflow Monitor replace the Server Manager - used to create sessions / workflows/ worklets to run, schedule, and monitor mappings for data movement

·        Repository Manager – used to maintain folders, users, permissions, locks, and repositories.

·        Integration Services – the “workhorse” of the domain. Informatica Server is the component responsible for the actual work of moving data according to the mappings developed and placed into operation. It contains several distinct parts such as the Load Manager, Data Transformation Manager, Reader and Writer.

·        Repository Services-  Informatica client tools and  Informatica Server connect to the repository database over the network through the Repository Server.