Oracle 1Z0-084 case studies
Oracle 1Z0-084 · Put your knowledge to work in context.
The Oracle Database SQL Certified Associate credential is an entry-level certification that verifies practical SQL skills against an Oracle Database. It suits developers, data analysts, report writers, application support staff, and students who need to query and change data rather than administer the server. The Oracle 1Z0-084 case studies are 5 cases and about 4,681 words.
1The Regional Dashboard That Adds Up to More Than 100%
OCEANIC RETAIL publishes a weekly regional dashboard from ORDERS (ORDER ID NUMBER primary key, REGION ID NUMBER NOT NULL, STATUS VARCHAR2(12) NOT NULL, ORDER TOTAL NUMBER, DISCOUNT PCT NUMBER). The table holds 48,210 rows: 3,140 have STATUS='CANCELLED' and a null ORDER TOTAL; 9,870 have a null DISCOUNT PCT.
908 words, about 5 min2The Outer Join That Returns Fewer Rows Than an Inner Join
The HR warehouse has DEPARTMENTS (DEPT ID primary key, DEPT NAME) with 27 rows, and EMPLOYEES (EMP ID primary key, LAST NAME, DEPT ID nullable, SALARY NOT NULL, COMMISSION PCT nullable). Three departments currently have no employees, and two contractors have DEPT ID null because they are on loan and not assigned anywhere.
911 words, about 5 min3The Nightly MERGE That Doubled the Warehouse
A distribution company loads stock levels into INVENTORY (INVENTORY ID NUMBER primary key from a sequence, PRODUCT ID NUMBER, WAREHOUSE ID VARCHAR2(10), QTY NUMBER CHECK (QTY = 0)). There is a non-unique index on (PRODUCT ID, WAREHOUSE ID) but deliberately no unique constraint, because 'the application enforces it'.
992 words, about 5 min4The Invoice Numbers With 132 Gaps
A billing system numbers invoices from a sequence: CREATE SEQUENCE seq inv START WITH 1000 INCREMENT BY 1 CACHE 20; a BEFORE INSERT trigger assigns seq inv.NEXTVAL whenever INVOICE NO is null. After one month the sequence reports 4,312 values issued but INVOICES holds 4,180 rows - 132 gaps.
941 words, about 5 min5The View That Broke When It Gained a Table
Schema SALES owns V MONTHLY, a reporting view over SALES.ORDERS and, since yesterday, SALES.SHIP COSTS. The view was created without any AUTHID clause.
929 words, about 5 min