4 key Difference Between Filter and Source Qualifier Transformation in Informatica

Below is in detailed Difference between Filter and Source Qualifier Transformation. In ETL Process both transformations play a different role and have different functionality. below is the Key Differences based on Functionality, Performance, Usage, Placement in the Data Flow etc.

Source Qualifier Transformation	Filter Transformation
Definition: The Source Qualifier transformation is an active transformation that represents the rows that Informatica reads from a source. It is automatically created when you add a relational or flat file source definition to a mapping.	Definition: The Filter transformation is an active transformation that allows you to filter rows based on a condition after they have been read from the source and passed through the Source Qualifier.
Purpose: It is used to join data originating from the same source database, filter rows when reading data, and specify sorted ports.	Purpose: It is used to filter rows in a mapping after the source data has been read and processed through the Source Qualifier.
Characteristics: 1. Connects directly to the source and converts source data types to the Informatica native data types. 2. Can apply SQL override to customize the SQL query that fetches data. 3. Can join data from multiple tables within the same source database. 4. Can perform filtering using SQL statements in the SQL override. 5. Can sort data before passing it downstream in the mapping	Characteristics: 1. Evaluate conditions row by row and remove rows that do not meet the condition. 2. Conditions are specified using Informatica’s expression language. 3. Filters data mid-stream in a mapping, after data has already been extracted.
Examples: 1. Filtering data directly in the SQL query (e.g. SELECT * FROM employees WHERE departmente = ‘IT’). 2. Joining multiple source tables (e.g. SELECT a., b. FROM orders a, customers b WHERE a.customer_id = b.customer_id).	Examples: 1. Filtering rows where the ‘department’ field is ‘Sales’ (e.g. department = ‘IT’). 2. Filtering rows where the ‘salary’ field is greater than 5000 (e.g. salary > 5000).

detailed comparison Filter and Source Qualifier Transformation

Filter and Source Qualifier Transformation Key Differences

Source Qualifier Transformation	Filter Transformation
Source Qualifier: Located directly after the source definition and before any other transformations.	Filter: Can be placed anywhere in the mapping after the Source Qualifier.

Placement in the Data Flow

Source Qualifier Transformation	Filter Transformation
Source Qualifier: Filters data at the source database level using SQL, joins multiple tables from the same source, and sorts data.	Filter: Filters rows based on conditions defined in Informatica’s expression language after the data has been fetched.

Functionality

Source Qualifier Transformation	Filter Transformation
Source Qualifier: Filtering data at the source level can improve performance by reducing the amount of data moved from the source to the target.	Filter: Filtering data mid-stream may be less efficient, especially with large data sets, as all rows must first be read into Informatica.

Performance

Source Qualifier Transformation	Filter Transformation
Source Qualifier: Used for initial data extraction and preliminary filtering, joining, and sorting.	Filter: Used for additional filtering and refining data within the mapping process after the initial extraction.

Usage