Mapping in Informatica
Mapping is a collection of source and target objects which is tied up together through a set of transformations. These transformations are formed with a set of rules that define how the data is loaded into the targets and flow of the data.
Mapping in Informatica includes the following set of objects, such as:
Why do we need Mapping?
In Informatica, Mapping is an object which can define the process of modification of the source data before it reaches the target object.
For example: Suppose an employee name as "Edward Cullen" in the source system and the target system. Now we need to have an employee name in the "Edward Cullen" format. At the mapping level, these kinds of operations are designed.
Mapping can define the data transformation details and source or target object characteristics because it is a primary object in the Informatica.
Mappings define the data transformation for each row at the individual column levels. And we can hold multiple sources and targets in a single mapping.
Components of Mapping
Here are some essential elements used in mapping, such as:
A mapping contains sources, targets, mapping parameters, variables, multiple changes, mapplets, and user-defined functions.
What is Stage Mapping?
In a stage mapping, we create the replica of the source table.
For Example, if we have a "Student" table, and we want to create an identical table, "Student_stage" in ETL schema.
A local stage table provides some advantages, such as production downtime, so it will not affect the ETL system because we have our own "Student_stage" table instead of referring to the "Student" table. There can be some other operations and processes which can affect the performance. The ETL processes will only access it when we have a replica staging table. Then it provides advantages with better performance.
In Stage Mappings,
For example, if the source table contains student details of rollno 1, 2, 3, and 10. The stage table is a kind of table which has student records of rollno 1 & 3 only.
In the data warehouse, we need to create stage tables to make the process of data transformation efficiently, to minimize the dependency of ETL or Data Warehouse from the real-time operating system. It could happen when we are fetching the relevant data only.
Mapping Parameters and Variables
Informatica has a way of defining parameters and variables as other programming languages. But Informatica is not a code-based language just like other programming languages.
In Informatica, we need to follow the predefined syntax and navigation to create parameters and variables.
Here are some fundamental differences between the mapping parameters and mapping variables, such as: