Oracle error: expression '' cannot be used as an assignment target - oracle

Question

When I try to execute the stored procedure, all the parameters that I pass to it, appears "expression '(parameter)' cannot be used as an assignment target", I don't know what the problem is.
This is the stored procedure:
create or replace PROCEDURE INSTERT_UPDATE_EMPLEADO
(
CEDULA IN OUT INTEGER,
ID_CARGO IN OUT INTEGER,
ID_EMP IN OUT INTEGER,
NOMBRE IN OUT VARCHAR,
APELLIDO IN OUT VARCHAR,
FECHA_NAC IN OUT INTEGER,
FECHA_CON IN OUT INTEGER,
SALARIO IN OUT INTEGER
) AS
BEGIN
IF ID_EMP = 0 THEN
INSERT INTO EMPLEADO("CEDULA_EMPLEADO", "ID_CARGO", "EMPLEADO_ID", "NOMBRE", "APELLIDO", "FECHA_NAC", "FECHA_CONTRATO", "SALARIO")
VALUES (CEDULA, ID_CARGO, ID_EMP, NOMBRE, APELLIDO, FECHA_NAC, FECHA_CON, SALARIO);
ELSE
UPDATE EMPLEADO SET NOMBRE = NOMBRE, APELLIDO = APELLIDO, FECHA_NAC = FECHA_NAC, FECHA_CONTRATO = FECHA_CON, SALARIO = SALARIO,
CEDULA_EMPLEADO = CEDULA, ID_CARGO = ID_CARGO WHERE EMPLEADO_ID = ID_EMP;
END IF;
COMMIT;
END INSTERT_UPDATE_EMPLEADO;

Answer 1

Since you are going to insert or update the table, you need to create the table first.
If you already have the table, please ignore this step:
create table EMPLEADO
(
CEDULA NUMBER(5),
ID_CARGO NUMBER(5),
ID_EMP NUMBER(5),
NOMBRE VARCHAR2(20),
APELLIDO VARCHAR2(20),
FECHA_NAC NUMBER(5),
FECHA_CON NUMBER(5),
SALARIO NUMBER(5)
)
Then create the stored procedure:
CREATE OR REPLACE PROCEDURE INSTERT_UPDATE_EMPLEADO(
P_CEDULA IN EMPLEADO.CEDULA%TYPE,
P_ID_CARGO IN EMPLEADO.ID_CARGO%TYPE,
P_ID_EMP IN EMPLEADO.ID_EMP%TYPE,
P_NOMBRE IN EMPLEADO.NOMBRE%TYPE,
P_APELLIDO IN EMPLEADO.APELLIDO%TYPE,
P_FECHA_NAC IN EMPLEADO.APELLIDO%TYPE,
P_FECHA_CON IN EMPLEADO.FECHA_CON%TYPE,
P_SALARIO IN EMPLEADO.SALARIO%TYPE)
IS
BEGIN
IF P_ID_EMP = 0 THEN
INSERT INTO EMPLEADO("CEDULA_EMPLEADO", "ID_CARGO", "EMPLEADO_ID", "NOMBRE", "APELLIDO", "FECHA_NAC", "FECHA_CONTRATO", "SALARIO")
VALUES (P_CEDULA, P_ID_CARGO, P_ID_EMP, P_NOMBRE, P_APELLIDO, P_FECHA_NAC, P_FECHA_CON, P_SALARIO);
ELSE
UPDATE EMPLEADO
SET NOMBRE = P_NOMBRE,
APELLIDO = P_APELLIDO,
FECHA_NAC = P_FECHA_NAC,
FECHA_CONTRATO = P_FECHA_CON,
SALARIO = P_SALARIO,
CEDULA_EMPLEADO = P_CEDULA,
ID_CARGO = P_ID_CARGO
WHERE EMPLEADO_ID = P_ID_EMP;
END IF;
COMMIT;
END;

Answer 2

The problem not in the procedure itself, but in its interface. out and in out parameters write their values back as output. For example:
create table demo (id integer);
Procedure (creates without errors):
create or replace procedure insert_demo
( id in out demo.id%type )
as
begin
insert into demo (id) values (id);
end insert_demo;
Call fails, because the literal value 1 can't be updated with the out value returned by the procedure:
SQL> exec insert_demo(1)
BEGIN insert_demo(1); END;
*
ERROR at line 1:
ORA-06550: line 1, column 19:
PLS-00363: expression '1' cannot be used as an assignment target
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored
If you are going to use out or in out parameters, you have to pass variables (SQL*Plus example below, though you could just call it from another procedure passing a normal PL/SQL variable):
SQL> var id number
SQL> exec :id := 1
PL/SQL procedure successfully completed.
ID
----------
1
SQL> exec insert_demo(:id)
PL/SQL procedure successfully completed.
ID
----------
1
The solution is therefore either to pass variables, or to change the parameter mode to in:
create or replace procedure insert_demo
( id in demo.id%type )
as
begin
insert into demo (id) values (id);
end insert_demo;
Test:
SQL> exec insert_demo(1)
PL/SQL procedure successfully completed.
It is generally good practice to avoid using column names for PL/SQL parameters and variables, for example by prefixing parameters with p_ and local variables with l_. Or if you must, you can use dot notation and the procedure name, e.g. insert_demo.id or instert_update_empleado.salario would specify the procedure parameter and not the table column. However, that is not the cause of the issue here.
(Also, your caps lock is on.)