Creating a Stored Procedure or Function in oralce

A stored procedure or function can be created with no parameters, IN parameters, OUT parameters, or IN/OUT parameters. There can be many parameters per stored procedure or function.

An IN parameter is a parameter whose value is passed into a stored procedure/function module. The value of an IN parameter is a constant; it can't be changed or reassigned within the module.

An OUT parameter is a parameter whose value is passed out of the stored procedure/function module, back to the calling PL/SQL block. An OUT parameter must be a variable, not a constant. It can be found only on the left-hand side of an assignment in the module. You cannot assign a default value to an OUT parameter outside of the module's body. In other words, an OUT parameter behaves like an uninitialized variable.

An IN/OUT parameter is a parameter that functions as an IN or an OUT parameter or both. The value of the IN/OUT parameter is passed into the stored procedure/function and a new value can be assigned to the parameter and passed out of the module. An IN/OUT parameter must be a variable, not a constant. However, it can be found on both sides of an assignment. In other words, an IN/OUT parameter behaves like an initialized variable.

This example creates stored procedures and functions demonstrating each type of parameter.

See also e281 Calling a Stored Procedure in a Database and e282 Calling a Function in a Database.

    try {
        // To create a connection to an Oracle database,
        // see e235 Connecting to an Oracle Database
        Statement stmt = connection.createStatement();
    
        // Create procedure myproc with no parameters
        String procedure =
            "CREATE OR REPLACE PROCEDURE myproc IS "
            + "BEGIN "
            + "INSERT INTO oracle_table VALUES('string 1'); "
            + "END;";
        stmt.executeUpdate(procedure);
    
        // Create procedure myprocin with an IN parameter named x.
        // IN is the default mode for parameter, so both `x VARCHAR' and `x IN VARCHAR' are valid
        procedure =
            "CREATE OR REPLACE PROCEDURE myprocin(x VARCHAR) IS "
            + "BEGIN "
            + "INSERT INTO oracle_table VALUES(x); "
            + "END;";
        stmt.executeUpdate(procedure);
    
        // Create procedure myprocout with an OUT parameter named x
        procedure =
            "CREATE OR REPLACE PROCEDURE myprocout(x OUT VARCHAR) IS "
            + "BEGIN "
            + "INSERT INTO oracle_table VALUES('string 2'); "
            + "x := 'outvalue'; " // Assign a value to x
            + "END;";
        stmt.executeUpdate(procedure);
    
        // Create procedure myprocinout with an IN/OUT parameter named x;
        // x functions as an IN parameter and also as an OUT parameter
        procedure =
            "CREATE OR REPLACE PROCEDURE myprocinout(x IN OUT VARCHAR) IS "
            + "BEGIN "
            + "INSERT INTO oracle_table VALUES(x); " // Use x as IN parameter
            + "x := 'outvalue'; "                    // Use x as OUT parameter
            + "END;";
        stmt.executeUpdate(procedure);
    
        // Create a function named myfunc which returns a VARCHAR value;
        // the function has no parameter
        String function =
            "CREATE OR REPLACE FUNCTION myfunc RETURN VARCHAR IS "
            + "BEGIN "
            + "RETURN 'a returned string'; "
            + "END;";
        stmt.executeUpdate(function);
    
        // Create a function named myfuncin which returns a VARCHAR value;
        // the function has an IN parameter named x
        function =
            "CREATE OR REPLACE FUNCTION myfuncin(x VARCHAR) RETURN VARCHAR IS "
            + "BEGIN "
            + "RETURN 'a return string'||x; "
            + "END;";
        stmt.executeUpdate(function);
    
        // Create a function named myfuncout which returns a VARCHAR value;
        // the function has an OUT parameter named x whose value is
        // returned to the calling PL/SQL block when the execution of the function ends
        function =
            "CREATE OR REPLACE FUNCTION myfuncout(x OUT VARCHAR) RETURN VARCHAR IS "
            + "BEGIN "
            + "x:= 'outvalue'; "
            + "RETURN 'a returned string'; "
            + "END;";
        stmt.executeUpdate(function);
    
        // Create a function named myfuncinout that returns a VARCHAR value;
        // the function has an IN/OUT parameter named x.  As an IN parameter, the value of x is
        // defined in the calling PL/SQL block before it is passed in eyfuncinout
        // function.  As an OUT parameter, the new value of x, `x value||outvalue', is also
        // returned to the calling PL/SQL block when the execution of the function ends.
        function =
            "CREATE OR REPLACE FUNCTION myfuncinout(x IN OUT VARCHAR) RETURN VARCHAR IS "
            + "BEGIN "
            + "x:= x||'outvalue'; "
            + "RETURN 'a returned string'; "
            + "END;";
        stmt.executeUpdate(function);
    } catch (SQLException e) {
    }