Мартин грубер понимание sql перевод Лебедева В. Н. Под редакцией Булычева В. Н. Москва, 1993 martin gruber

CREATE INDEX Mydate ON Orders(snum, odate);

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CREATE UNIQUE INDEX Combination ON Customers(snum, rating);
Глава 18

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CREATE TABLE Orders
(onum integer NOT NULL PRIMARY KEY,
amt decimal,
odate date NOT NULL,
cnum integer NOT NULL,
snum integer NOT NULL,
UNIOUE (snum, cnum));
или
CREATE TABLE Orders
(onum integer NOT NULL UNIQUE,
amt decimal,
odate date NOT NULL,
cnum integer NOT NULL,
snum integer NOT NULL,
UNIQUE (snum, cnum));
Первое решение предпочтительнее.

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CREATE TABLE Salespeople
(snum integer NOT NULL PRIMARY KEY,
sname char(15) CHECK (sname BETWEEN 'AA' AND 'MZ'),
city char(15),
comm decimal NOT NULL DEFAULT = .10);

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CREATE TABLE Orders
(onum integer NOT NULL,
amt decimal,
odate date,
cnum integer NOT NULL,
snum integer NOT NULL,
CHECK ((cnum > snum) AND (onum > cnum)));
Глава 19

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CREATE TABLE Cityorders
(onum integer NOT NULL PRIMARY KEY,
amt decimal,
cnum integer,
snum integer,
city char (15),
FOREIGN KEY (onum, amt, snum) REFERENCES Orders (onum, amt, snum),
FOREIGN KEY (cnum, city) REFERENCES Customers (cnum, city));

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CREATE TABLE Orders
(onum integer NOT NULL,
amt decimal,
odate date,
cnum integer NOT NULL,
snum integer,
prev integer,
UNIQUE (cnum, onum),
FOREIGN KEY (cnum, prev) REFERENCES Orders (cnum,onum));
Глава 20

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CREATE VIEW Highratings
AS SELECT *
FROM Customers
WHERE rating = (SELECT MAX (rating)
FROM Customers);

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