An example Analysis of Database trigger

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We maintain a customer table whose contents are not allowed to be modified on Saturdays and Sundays. This is the customer list:

CREATE TABLE plch_customers (custnum INTEGER, custname VARCHAR2)

I need to create a trigger to prevent any insertions, modifications, and deletions to this table over the weekend. I wrote this code:

CREATE OR REPLACE TRIGGER plch_customers_maint_trg / * TEXT*/DECLAREBEGIN IF TO_CHAR (SYSDATE, 'DY',' NLS_DATE_LANGUAGE=ENGLISH') IN ('SAT',' SUN') THEN RAISE_APPLICATION_ERROR (- 20000, 'Customers maintained Monday-Friday only.'); END IF;END;/

What options can be used to replace the / * TEXT*/, in the article so that this trigger does not allow any DML operations to be performed on the plch_ customers table over the weekend, and each statement is triggered only once?

(A)

BEFORE UPDATE ON plch_customers FOR EACH ROWBEFORE INSERT ON plch_customers FOR EACH ROWBEFORE DELETE ON plch_customers FOR EACH ROWSQL > CREATE OR REPLACE TRIGGER plch_customers_maint_trgBEFORE UPDATE ON plch_customers FOR EACH ROWBEFORE INSERT ON plch_customers FOR EACH ROWBEFORE DELETE ON plch_customers FOR EACH ROWDECLAREBEGIN IF TO_CHAR (SYSDATE, 'DY',' NLS_DATE_LANGUAGE=ENGLISH') IN ('SAT',' SUN') THEN RAISE_APPLICATION_ERROR (- 20000, 'Customers maintained Monday-Friday only.'); END IF END;ORA-04079: invalid trigger description SQL >

(B)

BEFORE UPDATE ON plch_customersBEFORE INSERT ON plch_customersBEFORE DELETE ON plch_customersSQL > CREATE OR REPLACE TRIGGER plch_customers_maint_trgBEFORE UPDATE ON plch_customersBEFORE INSERT ON plch_customersBEFORE DELETE ON plch_customersDECLAREBEGIN IF TO_CHAR (SYSDATE, 'DY',' NLS_DATE_LANGUAGE=ENGLISH') IN ('SAT',' SUN') THEN RAISE_APPLICATION_ERROR (- 20000, 'Customers maintained Monday-Friday only.'); END IF;END;ORA-04079: invalid trigger description SQL >

(C)

BEFORE UPDATE, INSERT OR DELETE ON plch_customersSQL > CREATE OR REPLACE TRIGGER plch_customers_maint_trgBEFORE UPDATE, INSERT OR DELETE ON plch_customersDECLAREBEGIN IF TO_CHAR (SYSDATE, 'DY',' NLS_DATE_LANGUAGE=ENGLISH') IN ('SAT',' SUN') THEN RAISE_APPLICATION_ERROR (- 20000, 'Customers maintained Monday-Friday only.'); END IF;END;ORA-00969: missing ON keyword SQL >

(D)

BEFORE UPDATE OR INSERT OR DELETE ON plch_customers FOR EACH ROWSQL > Trigger createdSQL >

(E)

BEFORE UPDATE OR INSERT OR DELETE ON plch_customersSQL > Trigger createdSQL >

Answer E

D is not the answer because each line is triggered and does not meet the condition.

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