Technical Development - Tiveloper.

Can automatically generate unique numbers Is a sharable object Can be used to create a primary key value Replaces application code Speeds up the efficiency of accessing sequence values when cached in memeory SyntaxCREATE SEQUENCE sequence [INCREMENT BY n] [START WITH n] [{MAXVALUE n | NOMAXVALUE}] [{MINVALUE n | NOMAXVALUE}] [{CYCLE | NOCYCLE}] [{CACHE n | NOCACHE}]; default increment value : 1 ..

Can automatically generate unique numbers Is a sharable object Can be used to create a primary key value Replaces application code Speeds up the efficiency of accessing sequence values when cached in memeory SyntaxCREATE SEQUENCE sequence [INCREMENT BY n] [START WITH n] [{MAXVALUE n | NOMAXVALUE}] [{MINVALUE n | NOMAXVALUE}] [{CYCLE | NOCYCLE}] [{CACHE n | NOCACHE}]; default increment value : 1 ..

CREATE OR REPLACE VIEW empvu10 (employee_number, employee_name, job_title) AS SELECT employee_id, last_name,job_id FROM employees WHERE department_id = 10 WITH READ ONLY; DROP VIEW view_name;

CREATE OR REPLACE VIEW empvu10 (employee_number, employee_name, job_title) AS SELECT employee_id, last_name,job_id FROM employees WHERE department_id = 10 WITH READ ONLY; DROP VIEW view_name;

CREATE OR REPLACE VIEW empvu20 AS SELECT * FROM employees WHERE department_id = 20 WITH CHECK OPTION CONSTRAINT empvu20_ck;No rows are updated because if the department number were to change to 10, the view would no longer be able to see that employee. With the WITH CHECK OPTION clause, therefore, the view can see only employees in department 20 and doesn't allow the department number for those ..

CREATE OR REPLACE VIEW empvu20 AS SELECT * FROM employees WHERE department_id = 20 WITH CHECK OPTION CONSTRAINT empvu20_ck;No rows are updated because if the department number were to change to 10, the view would no longer be able to see that employee. With the WITH CHECK OPTION clause, therefore, the view can see only employees in department 20 and doesn't allow the department number for those ..

DML operation on simple viewCannot remove or modify a row if the view contains the following: - Group function - A GROUP BY clause - The DISTINCT keyword - The pseudocolumn ROWNUM keyword - columns defined by expressions (only modify) Cannot add data through a view if the view includes - Group function - A GROUP BY clause - The DISTINCT keyword - The pseudocolumn ROWNUM keyword - columns defined..

DML operation on simple viewCannot remove or modify a row if the view contains the following: - Group function - A GROUP BY clause - The DISTINCT keyword - The pseudocolumn ROWNUM keyword - columns defined by expressions (only modify) Cannot add data through a view if the view includes - Group function - A GROUP BY clause - The DISTINCT keyword - The pseudocolumn ROWNUM keyword - columns defined..

Simple Views and Complex Views A simple view Derives data from only one table No functions or groups DML operations through the view A complex view more than one table contains functions and groups DML operation might be limited CREATE [OR REPLACE] [FORCE | NOFORCE] VIEW view_name [(alias[, alias] ... )] AS subquery [WITH CHECK OPTION [CONSTRAINT constraint]] [WITH READ ONLY [CONSTRAINT constrai..

Simple Views and Complex Views A simple view Derives data from only one table No functions or groups DML operations through the view A complex view more than one table contains functions and groups DML operation might be limited CREATE [OR REPLACE] [FORCE | NOFORCE] VIEW view_name [(alias[, alias] ... )] AS subquery [WITH CHECK OPTION [CONSTRAINT constraint]] [WITH READ ONLY [CONSTRAINT constrai..