How to pass parameter [bind variable or substitution variable] to a view?

Question

How can I pass a parameter [bind variable or substitution variable] to a view in Oracle?
Some will tell me that this is not necessary, that I can only pass the parameter when I query the view, but I found some case where this cause performance issue. In long view where I use subquery factoring [WITH], it's necessary to pass the parameter many time through different subqueries and not only to the resulting view.
In other database (SQL Server, Access), we can pass parameters through query. I can't find how to do that in Oracle. Can some one tell me what is the approach suggest by Oracle on that subject?
Thank you in advance,
MB
What I can do:
CREATE VIEW "HR"."EMP_NAME" ("FIRST_NAME", "LAST_NAME")
AS
SELECT FIRST_NAME, LAST_NAME FROM EMPLOYEES;
What I want to do:
CREATE VIEW "HR"."EMP_NAME" ("FIRST_NAME", "LAST_NAME")(prmEMP_ID)
AS
SELECT FIRST_NAME, LAST_NAME FROM EMPLOYEES WHERE EMPLOYEE_ID IN (:prmEMP_ID);

Answer 1

Blais wrote:
How can I pass a parameter [bind variable or substitution variable] to a view in Oracle?
Some will tell me that this is not necessary, that I can only pass the parameter when I query the view, but I found some case where this cause performance issue. In long view where I use subquery factoring [WITH], it's necessary to pass the parameter many time through different subqueries and not only to the resulting view.Yes, there can be performance issues. Views are a form of dynamic SQL and it is hard to predict how they will perform later.
You can't pass parameters to a view. They are not functions. The mechanism to put the values in is what you mentioned, passing the parameter when you query the view.
In other database (SQL Server, Access), we can pass parameters through query. I can't find how to do that in Oracle. Can some one tell me what is the approach suggest by Oracle on that subject? This functionality is not supported.
What I can do:
CREATE VIEW "HR"."EMP_NAME" ("FIRST_NAME", "LAST_NAME")
AS
SELECT FIRST_NAME, LAST_NAME FROM EMPLOYEES;
What I want to do:
CREATE VIEW "HR"."EMP_NAME" ("FIRST_NAME", "LAST_NAME")(prmEMP_ID)
AS
SELECT FIRST_NAME, LAST_NAME FROM EMPLOYEES WHERE EMPLOYEE_ID IN (:prmEMP_ID);Include the bind value when you use the view in a SELECT. The value will be applied to the view at run-time, somthing like
CREATE  VIEW "HR"."EMP_NAME_VW" ("FIRST_NAME", "LAST_NAME","EMPLOYEE_ID")(prmEMP_ID)
AS  SELECT FIRST_NAME, LAST_NAME FROM EMPLOYEES;
select *
  from emp_name_vw
  WHERE EMPLOYEE_ID IN (:prmEMP_ID);To use EMPLOYEE_ID I added it to your list of columns in the view so it can be referenced in the WHERE clause. If you don't want to see that value don't select it from the view.