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While learning Oracle Database, it is essential to understand the distinction between actual and formal parameters. Furthermore, the terms Actual Parameters and Formal Parameters are common in the programming profession.
If people ever mastered a programming language like Java or Dot Net, people undoubtedly come across one of these words. While working on the PL/SQL Functions and Stored Procedures series, they were frequently asked to define the distinction between PL/SQL Functions and Stored Procedures.
What Are Formal Parameters?
Any formal arguments for a subroutine or procedure must be specified at definition time. These parameters specify the list of possible variables, their placements, and their data types. When users define the formal parameters in the signature of their subroutines, there are no additional alternatives outside the default options that make a parameter alternative.
What are the Actual parameters?
Users’ real arguments when invoking a subroutine, such as a function or procedure. They give these variables to a subroutine when the user calls it. An actual parameter need not be supplied when executing a procedure when a formal parameter has a binary output.
Difference between Formal and Actual Parameters
| Formal parameters | Actual Parameters |
| When formal parameters are used in the function header, they can be considered the function’s local variables. | Variable names or constant values can be used as actual arguments. |
| Formal parameters are those that are mentioned in the function definition | The parameters that are given in a function call are the actual arguments |
| The receiving value’s data type has to be stated. | The data does not have to be stated for the argument itself. |
| A subprogram’s formal parameters are its specifications | The real parameters are those that are present in the calling subprogram. |
| The parameter list of a subprogram specification refers to these variables or phrases. | These are the variables or expressions that the argument list of a subprogram call references |
| Formal parameters are used in function definition statements and are expressed with a type of data at their declaration. | A function’s arguments or actual parameters are the values (expressions) passed to it when it is called. |
Can formal and actual parameters have the same names?
Both of them should be defined by the variables in their respective contexts. For instance, it may be compared and 2 (formal parameters) in the context of techniques. However, the call’s actual arguments may be my pyjamas and my aunts, Pyjamas. Whether they “mean” the same thing in either circumstance doesn’t matter.
Parameter modes in PL/SQL
There are three possible choices for PL/SQL procedure parameters: IN, OUT, or IN OUT. For PL/SQL functions, parameters can only be IN.
An IN formal parameter defaults to the actual argument used to invoke it unless a default value was explicitly initialised. The caller application references the IN parameter but does not modify its value. Even when control is restored to the calling programme, the actual argument always retains the value that it had when it was set before the call and other aspects.
An OUT formal parameter’s initial value is the actual parameter used to call it. The calling programme may reference the formal parameter and supply updated values. If the called programme ends properly, the most recent value of the formal parameter is applied to the real parameter. The most recent value of the formal parameter is applied to the actual parameter in the case of a managed exception. The value of the real parameter is unaffected and the same as before the call, even if an unintended exception occurs.
An IN OUT formal component is initialised to the real parameter it was called, just like an IN parameter is. In the same way, an OUT parameter is adjustable by the called programme, and an IN OUT formal parameter is also adjustable by the called programme.
If the called programme terminates without raising an exception, the final value of the formal parameter is delivered to the calling program’s actual parameter. The most recent value of the formal parameter is applied to the actual parameter in the case of a managed exception.
