Passive and connected
transformation.
Use the Expression
transformation to calculate values in a single row before we write to the
target. For example, we might need to adjust employee salaries, concatenate
first and last names, or convert strings to numbers.
Use the Expression
transformation to perform any non-aggregate calculations.
Example: Addition,
Subtraction, Multiplication, Division, Concat, Uppercase conversion, lowercase
conversion etc.
We can also use the
Expression transformation to test conditional statements before we output the
results to target tables or other transformations. Example: IF, Then, Decode
There are 3 types of
ports in Expression Transformation:
- Input
- Output
- Variable:
Used to store any temporary calculation.
Calculating
Values :
To use the Expression
transformation to calculate values for a single row, we must include the
following ports:
- Input
or input/output ports for each value used in the calculation: For example:
To calculate Total Salary, we need salary and commission.
- Output
port for the expression: We enter one expression for each output port.
The return value for the output port needs to match the return value of
the expression.
We can enter multiple
expressions in a single Expression transformation. We can create any number of
output ports in the transformation.
No comments:
Post a Comment