Informatica Mapping variable values are persistence between two session runs.Generally we all get feeling that it value would be changing , Few Handy tips to understand the difference between informatica mapping parameter and variable.
Informatica Mapping Parameter:
Value of mapping parameter remain constant for a session run. Server reads its value on every run from parameter file. its value can not be changed at the time of session execution. When ever next time session runs, it reads the parameter value again from parameter file.
Value of mapping variable can change in-between session run. You can write code to assign some value to it.Server saves the latest value of a mapping variable in repository. This variable value can be used at session/mapping run.
Session parameters are used to keep information like connection and path information. Database connection, Source and target file path etc. Generally User defined parameters keeps sll connections and File Paths.Inbuilt parameters keeps Server and run time information.