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PSUEDO Column :Level and Connect By Clause in Oracle SQL

PSUEDO Column: Level and Connect By Clause Q: How to Implement Loop in Oracle SQL? > "LEVEL" is a System Variable (PSUEDO Column) > By default LEVEL initialized with 1 > By default LEVEL incremented by 1 Ex: Initially 1 1+1=2 2+1=3 ....etc. SELECT LEVEL FROM DUAL CONNECT BY LEVEL

ROWNUM and ROWID Psuedo Columns usage in Oracle SQL

ROWNUM and ROWID Psuedo Columns usage in Oracle SQL Importance of Psuedo Columns Frequently used Psuedo Columns in Oracle SQL: 1.ROWID 2.ROWNUM 3.CURRVAL 4.NEXTVAL 5.LEVEL CONNECT BY Q:How to display rowids for any table in Oracle SQL? SELECT ROWID,EMPNO,ENAME,SAL FROM EMP; ROWID is a physical address in DB. It is used to delete duplicate records. It contains 18-Digits(alpha-numeric.)-Base-64 String Example :- CREATE TABLE EMP77 ( ENO NUMBER(4), ENAME VARCHAR2(50), SAL NUMBER(10, 2) ); INSERT INTO EMP77 (ENO, ENAME, SAL) VALUES (101, 'ARJUN', 55000); INSERT INTO EMP77 (ENO, ENAME, SAL) VALUES (102, 'BEATRICE', 62000); INSERT INTO EMP77 (ENO, ENAME, SAL) VALUES (103, 'CHENG', 48500); INSERT INTO EMP77 (ENO, ENAME, SAL) VALUES (104, 'DAHLIA', 71000); INSERT INTO EMP77 (ENO, ENAME, SAL) VALUES (105, 'ELIAS', 53000); INSERT INTO EMP77 (ENO, ENAME, SAL) VALUES (101, 'ARJUN', 55000); E...

Sequences in Oracle SQL

ABOUT SEQUENCES in Oracle SQL Definitions:- A Sequence is a DB object created to generate sequence numbers(integers) automatically. It's primary use to create auto-increment values for Surrogate Keys or Pimary Key Columns without manual intervention. Syntax: CREATE SEQUENCE [START WITH ] [INCREMENT BY ] [MAXVALUE ] [MINVALUE ] [CYCLE/NOCYCLE] [CACHE ]; OR CREATE SEQUENCE [START WITH n] [INCREMENT BY n] [MAXVALUE n | NOMAXVALUE] [MINVALUE n | NOMINVALUE] [CYCLE | NOCYCLE] [CACHE n | NOCACHE] [ORDER | NOORDER]; Example 1 :- CREATE SEQUENCE S1 START WITH 1 INCREMENT BY 1 MAXVALUE 5; using sequence :- -------------------------- CREATE TABLE STUDENT ( SID NUMBER(2), SNAME VARCHAR2(10) ); INSERT INTO STUDENT VALUES(S1.NEXTVAL , 'A'); INSERT INTO STUDENT VALUES(S1.NEXTVAL , 'B'); INSERT INTO STUDENT VALUES(S1.NEXTVAL , 'C'); INSERT INTO STUDENT VALUES...

HCM Cloud Interview Questions

1. Which column serves as the primary 'Golden Thread' to link a person's identity (Names/Phones) to their employment records (Assignments) in Oracle HCM Cloud? A.PERSON_ID(correct:The PERSON_ID is the universal unique identifier for an individual across all HCM modules.) B.PERIOD_OF_SERVICE_ID C.ASSIGNMENT_ID D.PERSON_NUMBER 2.When querying the table PER_ALL_PEOPLE_F, why is it critical to include the condition: TRUNC(SYSDATE) BETWEEN effective_start_date AND effective_end_date? A.To automatically join the Assignment table B.To filter out terminated employees C.To improve query performance via indexing D.To prevent duplicate rows for the same person(correct: Because the table is date-tracked, every historical change creates a new row; this clause ensures you only get the current version.) 3.You need to pull a list of Department names for a report. Which table stores the 'User-Friendly' name of the department in a specific language? A.PER_DEPARTMENTS B.FND_LOOKUP_VA...

Demo Tables in Oracle SQL for practice

Employee Table Creation and Insertion Scripts in Oracle SQL =========================================================== CREATE TABLE EMP ( EMPNO NUMBER(4) NOT NULL, ENAME VARCHAR2(10), JOB VARCHAR2(9), MGR NUMBER(4), HIREDATE DATE, SAL NUMBER(7, 2), COMM NUMBER(7, 2), DEPTNO NUMBER(2)); INSERT ALL INTO EMP VALUES (7369, 'SMITH', 'CLERK', 7902, TO_DATE('17-DEC-1980', 'DD-MON-YYYY'), 800, NULL, 20) INTO EMP VALUES (7499, 'ALLEN', 'SALESMAN', 7698, TO_DATE('20-FEB-1981', 'DD-MON-YYYY'), 1600, 300, 30) INTO EMP VALUES (7521, 'WARD', 'SALESMAN', 7698, TO_DATE('22-FEB-1981', 'DD-MON-YYYY'), 1250, 500, 30) INTO EMP VALUES (7566, 'JONES', 'MANAGER', 7839, TO_DATE('02-APR-1981', 'DD-MON-YYYY'), 2975, NULL, 20) INTO EMP VALUES (7654, 'MARTIN', 'SALESMAN', 7698, T...

ORA:12541 cannot connect. no listener at host localhost port 1521

How to resolve "Test failed: ORA-12541: Cannot connect. No listener at host localhost" 1. Write SQL query to get SID: select * from global_name; FREE 2. Qpen Services and check these three services running or not, if not start. To open service use: windows icon+r type services.msc a. OracleJobSchedulerFREE --- Must Running. b. OracleOraDB23Home1TNSListener --- Must Running. c. OracleServiceFREE --- Must Running. 3. D:\app\karra\product\23ai\dbhomeFree\NETWORK\ADMIN\/istener.ora Check hostname and copy same host name and replace with localhost. 192.168.1.40 lsnrctl status lsnrctl start ORCL = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP) (HOST = localh (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orcl.opentext.net ) app > usuario > product > 21c > homes > OraDB21Home1 > network > admin listenes sqlnet sqlnet23112611PM4112.bak tnsnames