How to create the correct trigger instead of insert or update? ORACLE. Trigger. pl/sql

Help create a trigger for a non-updatable view.

The tables look like this.

 CREATE TABLE Users(id_user INTEGER GENERATED ALWAYS AS IDENTITY(START with 1 INCREMENT by 1 NOCACHE) PRIMARY KEY,
                surname VARCHAR2(30) NOT NULL,
                name VARCHAR2(30) NOT NULL,
                patronymic VARCHAR2(30) NULL,
                tel_no VARCHAR2(17) NOT NULL,
              
                CONSTRAINT ch_telno_users
                           CHECK(REGEXP_LIKE(tel_no, '^+375(d{2})d{3}-d{2}-d{2}$')),
                CONSTRAINT uni_telno_users
                           UNIQUE(tel_no)
                 );


CREATE TABLE Software(id_sw INTEGER GENERATED ALWAYS AS IDENTITY(START with 1 INCREMENT by 1 NOCACHE) PRIMARY KEY,
                  name_sw VARCHAR2(40) NOT NULL,
                  version VARCHAR2(10) NULL,
                  license_period VARCHAR2(10) NOT NULL,
                  id_mfr INTEGER NOT NULL,
                  release_date DATE NOT NULL,
                  price NUMBER(9,2),
                  total_amount INTEGER NOT NULL,
                CONSTRAINT id_mfr_fk
                           FOREIGN KEY(id_mfr)
                           REFERENCES Manufacturer,           
                  );

    CREATE SYNONYM sw for Software;


CREATE TABLE Sales(id_sale INTEGER GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
               id_user INTEGER NOT NULL,
               id_sw INTEGER NOT NULL,
               quantity INTEGER NOT NULL,
               total_cost NUMBER(9,2),
               order_date DATE NOT NULL CHECK (order_date >= to_date('01/01/2019', 'dd/mm/yyyy')),
               expiration_date DATE NOT NULL,
             CONSTRAINT id_user_fk
                        FOREIGN KEY(id_user)
                        REFERENCES Users,
             CONSTRAINT id_sw_fk
                        FOREIGN KEY(id_sw)
                        REFERENCES Software
            );

The view itself looks like this

    CREATE OR REPLACE VIEW SalesView AS
    SELECT Sales.id_sale,sw.name_sw||' '||sw.version sw_full_name,        
    Users.surname||' '||Users.name||' '||Users.patronymic user_full_name,  
    sales.quantity,         sales.order_date
    FROM sw INNER JOIN (Users INNER JOIN Sales ON Sales.id_user = Users.id_user)  ON sw.id_sw = sales.id_sw;

I tried to create a trigger like this. But for some reason it is not created.( Error at line 86: PL/SQL: SQL Statement ignored Error at line 94: PL/SQL: ORA-00917: missing comma)

it seems to me that I went the hard way. help fix this code.

    CREATE OR REPLACE TRIGGER sales_view_instead_of_trig INSTEAD OF
    UPDATE OR INSERT ON salesview
    FOR EACH ROW
      DECLARE
      sw_new        sw.id_sw%TYPE;
      user_new      Users2.id_user%TYPE;
      check_excep_sw   VARCHAR2(51);
      check_excep_user VARCHAR2(92);
    BEGIN
        IF updating THEN --* update
    IF :new.sw_full_name != :old.sw_full_name THEN
        SELECT
            sw.name_sw||' '||sw.version
        INTO check_excep_sw
        FROM
            sw
        WHERE
            sw.name_sw||' '||sw.version = :new.sw_full_name;
        SELECT
            id_sw
        INTO sw_new
        FROM
            sw
        WHERE
            sw.name_sw||' '||sw.version = :new.sw_full_name;
      ELSE
        SELECT
            id_sw
        INTO sw_new
        FROM
            sw
        WHERE
            sw.name_sw||' '||sw.version = :old.sw_full_name;
       END IF;
       IF :new.user_full_name != :old.user_full_name THEN
        SELECT
            Users2.surname||' '||Users2.name||' '||Users2.patronymic
        INTO check_excep_user
        FROM
            Users2
        WHERE
            Users2.surname||' '||Users2.name||' '||Users2.patronymic = :new.user_full_name;
        SELECT
            id_user
        INTO user_new
        FROM
            Users2
        WHERE
            Users2.surname||' '||Users2.name||' '||Users2.patronymic = :new.user_full_name;
       ELSE
        SELECT
            id_user
        INTO user_new
        FROM
            Users2
        WHERE
            Users2.surname||' '||Users2.name||' '||Users2.patronymic = :old.user_full_name;
        END IF;
       UPDATE sales
       SET
        id_user = user_new,
        id_sw = sw_new,
        quantity = :new.quantity,
        order_date = :new.order_date,
        expiration_date = :new.expiration_date,
        total_cost = :new.total_cost
    WHERE
        id_sale = :old.id_sale;
   END IF;
    IF inserting THEN --* insert
   SELECT sw.name_sw||' '||sw.version INTO check_excep_sw
        FROM sw
        WHERE sw.name_sw||' '||sw.version = :new.sw_full_name;
        SELECT id_sw
        INTO sw_new
        FROM sw
        WHERE sw.name_sw||' '||sw.version = :new.sw_full_name;
    SELECT
        Users2.surname||' '||Users2.name||' '||Users2.patronymic
    INTO check_excep_user
    FROM
        Users2
    WHERE
        Users2.surname||' '||Users2.name||' '||Users2.patronymic = :new.user_full_name;
     SELECT id_user
        INTO user_new
        FROM Users2
        WHERE Users2.surname||' '||Users2.name||' '||Users2.patronymic = :new.user_full_name;
    INSERT INTO sales(
        id_user,
        id_sw,
        quantity,
        order_date,
        expiration_date,
        total_cost
     ) VALUES (
        id_user = user_new,
        id_sw = sw_new,
        quantity = :new.quantity,
        order_date = :new.order_date,
        expiration_date = :new.expiration_date,
        total_cost = :new.total_cost
     );
        END IF;
    EXCEPTION
        WHEN no_data_found THEN
    dbms_output.put_line('-------------------------------------------');
    dbms_output.put_line('| ERROR!   |');
    dbms_output.put_line('-------------------------------------------');
    END;
    /

Answer

You say that you’re getting an error creating the trigger. But if I try to replicate your problem, I can’t because the definition of the Software table is invalid. First, the foreign key references a table Manufacturer that doesn’t exist in your example. And second, the foreign key constraint definition has an extra comma at the end.

If I remove the foreign key constraint entirely

CREATE TABLE Software(id_sw INTEGER GENERATED ALWAYS AS IDENTITY(START with 1 INCREMENT by 1 NOCACHE) PRIMARY KEY,
                  name_sw VARCHAR2(40) NOT NULL,
                  version VARCHAR2(10) NULL,
                  license_period VARCHAR2(10) NOT NULL,
                  id_mfr INTEGER NOT NULL,
                  release_date DATE NOT NULL,
                  price NUMBER(9,2),
                  total_amount INTEGER NOT NULL
                  );

That allows the script to get as far as trying to create the trigger. At that point, you’ll get errors which include (but are not limited to) the ORA-00917 error you mentioned.

Errors: TRIGGER SALES_VIEW_INSTEAD_OF_TRIG
Line/Col: 62/27 PLS-00049: bad bind variable 'NEW.EXPIRATION_DATE'
Line/Col: 63/22 PLS-00049: bad bind variable 'NEW.TOTAL_COST'
Line/Col: 86/5 PL/SQL: SQL Statement ignored
Line/Col: 94/17 PL/SQL: ORA-00917: missing comma
Line/Col: 98/27 PLS-00049: bad bind variable 'NEW.EXPIRATION_DATE'
Line/Col: 99/22 PLS-00049: bad bind variable 'NEW.TOTAL_COST'

The PLS-00049: bad bind variable errors occur because there are no columns called expiration_date or total_cost in the definition of the view. Thus, there is no such thing as :new.expiration_date or :new.total_cost because DML against the view cannot specify values for those columns. I have no idea how you want to handle that– either omit the values, provide default values, read the values from somewhere else, add the columns to the view and provide them in the DML against the view, etc. The fact that expiration_date is defined as not null seemingly limits your options.

If you look at line 86 of your trigger, you’ll see this statement

INSERT INTO sales(
        id_user,
        id_sw,
        quantity,
        order_date,
        expiration_date,
        total_cost
     ) VALUES (
        id_user = user_new,
        id_sw = sw_new,
        quantity = :new.quantity,
        order_date = :new.order_date,
        expiration_date = :new.expiration_date,
        total_cost = :new.total_cost
     );

which isn’t syntactically valid.

INSERT INTO sales(
        id_user,
        id_sw,
        quantity,
        order_date,
        expiration_date,
        total_cost
     ) VALUES (
        user_new,
        sw_new,
        :new.quantity,
        :new.order_date,
        :new.expiration_date,
        :new.total_cost
     );

would be valid if :new.expiration_date and :new.total_cost were valid identifiers. But, as mentioned above, they’re not valid. And it isn’t obvious what you would want the values to be on insert.

Here is a liveSQL example that you can play with to make sure what you have is a reproducible test case.