такими, как эти: SELECT AU.MAKE, AU.MODEL, AU.WEIGHT, AU.PRICE, AU.IN_STOCK FROM AUTOMOBILES AU WHERE (AU.MAKE = :MAKE OR :MAKE IS NULL) AND (AU.MODEL = :MODEL OR :MODEL IS NULL) AND (AU.PRICE <= :MAXPRICE состоит в том, что конечный пользователь может дополнительно ввести варианты для параметров :make, :model и :maxprice. Там, где сделан выбор, должен быть применен соответствующий фильтр. Везде, где :make, :model и :maxprice. существует только на уровне приложений. Прежде чем запрос передается серверу Firebird для подготовки, он должен быть преобразован в такую форму: SELECT AU.MAKE, AU.MODEL, AU.WEIGHT

.......................................................................... 12 Choosing a Server Model ................................................................................................. chapter, Known Compatibility Issues before you set out to install Firebird 2.0. Choosing a Server Model Classic, Superserver and Embedded are all the same Firebird engine. The differences are in the ways “full servers” because Firebird also supports an embedded server on both Windows and POSIX. In this model, intended for “stand-alone” deployments, a local client and a server are rolled together into one

EXISTS. Например, следующий запрос: Общие элементы языка 84 SELECT model, speed, hd FROM PC WHERE model IN (SELECT model FROM product WHERE maker = 'A'); использованием предиката EXISTS: SELECT model, speed, hd FROM PC WHERE EXISTS (SELECT * FROM product WHERE maker = 'A' AND product.model = PC.model); существуют модели, производитель которых начинается на букву «A»: SELECT model, speed, hd FROM PC WHERE model IN (SELECT model FROM product WHERE maker STARTING WITH 'A'); См

ARRAY Type The support of arrays in the Firebird DBMS is a departure from the traditional relational model. Supporting arrays in the DBMS could make it easier to solve some data-processing tasks involving SELECT model, speed, hd FROM PC WHERE model IN (SELECT model FROM product WHERE maker = 'A'); can be replaced with a similar one using the EXISTS predicate: SELECT model, speed WHERE EXISTS (SELECT * FROM product WHERE maker = 'A' AND product.model = PC.model); However, a query using NOT IN with a subquery does not always give the same result as its

arrays. The support of arrays in the Firebird DBMS is a departure from the traditional relational model. Supporting arrays in the DBMS could make it easier to solve some data-processing tasks involving SELECT model, speed, hd FROM PC WHERE model IN (SELECT model FROM product WHERE maker = 'A'); can be replaced with a similar one using the EXISTS predicate: SELECT model, speed WHERE EXISTS (SELECT * FROM product WHERE maker = 'A' AND product.model = PC.model); Chapter 4. Common Language Elements 99 However, a query using NOT IN with a subquery does

de- fined scope even if it has sufficient rights on the database files. Choose your authentication model (2.1 only) Firebird 2.1 and higher support three authentication models when connecting to databases account name. On Linux, the mixed model is used. On Windows, the default is mixed in 2.1, 2.1.1 and 2.1.2, and native in 2.1.3 and higher. You can change the model by setting the Authentication parameter Wrapped programlistings in blockquotes. Security: Added new varlistentry Choose your authentication model (2.1 only). Working with databases :: Creating a database using isql :: Starting isql: Added “# means

Abfrage: SELECT model, speed, hd FROM PC WHERE model IN (SELECT model FROM product WHERE maker = 'A'); kann ersetzt werden mittels EXISTS-Prädikat: SELECT model, speed, hd FROM WHERE maker = 'A' Chapter 4. Allgemeine Sprachelemente 87 AND product.model = PC.model); Jedoch gilt zu beachten, dass eine Abfrage mittels NOT IN und einer Unterabfrage nicht immer Computer, die deren Hersteller mit dem Buchstaben “A” beginnt: SELECT model, speed, hd FROM PC WHERE model IN (SELECT model FROM product WHERE maker STARTING WITH 'A'); Siehe