💥 اولین و تنها‌ترین پاسخ‌نامه تشریحی سوالات پایگاه داده کنکور ارشد مهندسی کامپیوتر ۱۴۰۳:
۱۰۹. گزینه سوم
طبق کتاب سیلبرشاتز:
In general, an SQL view is said to be updatable (i.e., inserts, updates, or deletes can
be applied on the view) if the following conditions are all satisfied by the query defining
the view:
۱۱۰. گزینه چهار
طبق کتاب سیلبرشاتز:
Instead, the delete “cascades” to the course
relation, deleting the tuple that refers to the department that was deleted. Similarly, the
system does not reject an update to a field referenced by the constraint if it violates the
constraint; instead, the system updates the field dept name in the referencing tuples in
course to the new value as well
۱۱۱. گزینه یک
طبق مرجع سیلبرشاتز چالش اصلی تکامل اسکیما، همان گزینه اول است.
Database design is usually not a one-time activity. The needs of an organization evolve
continually, and the data that it needs to store also evolve correspondingly. During
the initial database-design phases, or during the development of an application, the
database designer may realize that changes are required at the conceptual, logical, or
physical schema levels. Changes in the schema can affect all aspects of the database
application. A good database design anticipates future needs of an organization and
ensures that the schema requires minimal changes as the needs evolve.
۱۱۲. چهارم
طبق سیلبرشاتز:
Specialization
An entity set may include subgroupings of entities that are distinct in some way from
other entities in the set. For instance, a subset of entities within an entity set may have
attributes that are not shared by all the entities in the entity set. The E-R model provides
a means for representing these distinctive entity groupings.
In terms of an E-R diagram, specialization is depicted by a hollow arrow-head pointing
from the specialized entity to the other entity (see Figure 6.18). We refer to this relationship
as the ISA relationship, which stands for “is a” and represents, for example,
that an instructor “is a” employee.
۱۱۳. گزینه سوم
مورد اول غلطه ما نام دپارتمان میخواییم رفته ایدی برگردونده
موردم دوم غلطه دپارتمان‌هایی که بدون کارمند باشن رو هم برمیگردونه
مورد سوم درسته چون دقیقا کارمندانی دپارتمان‌ها رو برمیگردونه
مورد چهارم درست نیست اومده ایدی دپارتمان رو با ایدی کارمند تطابق داده
۱۱۴. گزینه سوم (این تست در کلید نهایی حذف گردید😐)
گزینه اول و آخر نیست یه نگاه کنید برای این مواقع اسرشن به کار برده مرجع نه تریگر مورد اول هم که غطه کلا.
گزینه دوم ظاهرا خطای نحوی داره و گزینه سومه
۱۱۵. گزینه دوم
دو مورد آخر غلطه فقط
#پایگاه
۱۰۹. گزینه سوم
طبق کتاب سیلبرشاتز:
In general, an SQL view is said to be updatable (i.e., inserts, updates, or deletes can
be applied on the view) if the following conditions are all satisfied by the query defining
the view:
۱۱۰. گزینه چهار
طبق کتاب سیلبرشاتز:
Instead, the delete “cascades” to the course
relation, deleting the tuple that refers to the department that was deleted. Similarly, the
system does not reject an update to a field referenced by the constraint if it violates the
constraint; instead, the system updates the field dept name in the referencing tuples in
course to the new value as well
۱۱۱. گزینه یک
طبق مرجع سیلبرشاتز چالش اصلی تکامل اسکیما، همان گزینه اول است.
Database design is usually not a one-time activity. The needs of an organization evolve
continually, and the data that it needs to store also evolve correspondingly. During
the initial database-design phases, or during the development of an application, the
database designer may realize that changes are required at the conceptual, logical, or
physical schema levels. Changes in the schema can affect all aspects of the database
application. A good database design anticipates future needs of an organization and
ensures that the schema requires minimal changes as the needs evolve.
۱۱۲. چهارم
طبق سیلبرشاتز:
Specialization
An entity set may include subgroupings of entities that are distinct in some way from
other entities in the set. For instance, a subset of entities within an entity set may have
attributes that are not shared by all the entities in the entity set. The E-R model provides
a means for representing these distinctive entity groupings.
In terms of an E-R diagram, specialization is depicted by a hollow arrow-head pointing
from the specialized entity to the other entity (see Figure 6.18). We refer to this relationship
as the ISA relationship, which stands for “is a” and represents, for example,
that an instructor “is a” employee.
۱۱۳. گزینه سوم
مورد اول غلطه ما نام دپارتمان میخواییم رفته ایدی برگردونده
موردم دوم غلطه دپارتمان‌هایی که بدون کارمند باشن رو هم برمیگردونه
مورد سوم درسته چون دقیقا کارمندانی دپارتمان‌ها رو برمیگردونه
مورد چهارم درست نیست اومده ایدی دپارتمان رو با ایدی کارمند تطابق داده
۱۱۴. گزینه سوم (این تست در کلید نهایی حذف گردید😐)
گزینه اول و آخر نیست یه نگاه کنید برای این مواقع اسرشن به کار برده مرجع نه تریگر مورد اول هم که غطه کلا.
گزینه دوم ظاهرا خطای نحوی داره و گزینه سومه
۱۱۵. گزینه دوم
دو مورد آخر غلطه فقط
#پایگاه
![[ ɴᴇᴡ ᴡᴏʀʟᴅ 1400 ]](/avatar/1098/1098691995.jpg)
