CREATE SEQUENCE name INCREMENT BY n START WITH

Создание последовательности Определение последовательности для автоматической генерации чисел. CREATE SEQUENCE name [INCREMENT BY n] [START WITH n] [{MAXVALUE n | NOMAXVALUE}] [{MINVALUE n | NOMINVALUE}] [{CYCLE | NOCYCLE}] [{CACHE n | NOCACHE}] ПРИМЕР: Создать последовательность S_DEPT_ID для первичного ключа таблицы S_DEPT. Параметр CYCLE использоваться не должен. SQL> CREATE SEQUENCE s_dept_id 2 INCREMENT BY 1 3 START WITH 51 4 MAXVALUE 9999999 5 NOCACHE 6 NOCYCLE; Sequence created. 3 А. М. Гудов

Что такое представление? ID LAST_NAME -- ------1 Velasquez 2 Ngao 3 Nagayama 4 Quick-To-See 5 Ropeburn 6 Urguhart 7 Menchu 8 Biri 9 Catchpole 10 Havel 11 Magee 12 Giljum Sedeghi EMPVU 45 View 13 14 Nguyen LAST_NAME TITLE 15 Dumas 16 Maduro --------------17 Smith 18 Nozaki Havel Warehouse Manager 19 Patel Dancs Stock Clerk 20 Newman 21 Markarian Schwartz Stock Clerk 22 Chang 23 Patel 24 Dancs 25 Schwartz S_EMP Table ID -10 24 25 9 FIRST_NAME -----Carmen La. Doris Midori Mark Audry Molly Roberta Ben Antoinette Marta Colin Henry Yasmin Mai Andre Elena George Akira Vikram Chad Alexander Eddie Radha Bela Sylvie TITLE DEPT_ID ----------President 50 VP, Operations 41 VP, Sales 31 VP, Finance 10 VP, Administration 50 Warehouse Manager 41 Warehouse Manager 42 Warehouse Manager 43 Warehouse Manager 44 Warehouse Manager 45 Sales Representative 31 Sales Representative 32 Sales Representative 33 Sales Representative 34 Sales Representative 35 Stock Clerk 41 Stock Clerk 42 Stock Clerk 43 Stock Clerk 44 Stock Clerk 34 Stock Clerk 45 А. М. Гудов

Создание сложного представления с групповыми функциями для выборки данных из двух таблиц. SQL> 2 3 4 5 6 7 View 14 CREATE VIEW dept_sum_vu (name, minsal, maxsal, avgsal) AS SELECT d. name, MIN(e. salary), MAX(e. salary), AVG(e. salary) FROM s_emp e, s_dept d WHERE e. dept_id = d. id GROUP BY d. name; created. А. М. Гудов

Структура индекса в виде B-дерева Giljum Ngao Biri Giljum Menchu Ngao Ngu Sedeghi Velasquez 22 Nguyen Sedeghi Urguhart Velasquez ROWID ID -1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 LAST_NAME ------Velasquez Ngao Nagayama Quick-To-See Ropeburn Urguhart Menchu Biri Catchpole Havel Magee Giljum Sedeghi Nguyen Dumas Maduro Smith Nozaki Patel Newman Markarian Chang Patel Dancs Schwartz А. М. Гудов