Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
It defines that no primary key value can be null. This is as the primary key is used to recognize individual tuple in the relation. So we will not be able to recognize the records uniquely containing null values for the primary key attributes. This constraint is specified on single individual relation.
Example: Let R be the Table
A#
B
C
Null
B1
C1
A2
B2
C2
B3
C3
A4
B4
A5
C5
Note:
1) '#' shows the Primary key of a relation.
In the relation R above, the primary key has null values in the tuples t1 & t3. NULL value in primary key is not allowed, therefore, relation instance is an invalid instance.
Why does a DBMS query language is designed? A DBMS query language is designed to support end users who use English-like commands. support in the development of complex applicat
Describe Dynamic Model. The dynamic model specifies allowable sequences of changes to the objects from an object model. It contains event trace diagrams describing scenarios. A
Where does view definition stored? A view definition is permanently stored as part of the database.
CREATE TABLE prodtrans ( pno number (4) ptype char (1) CHECK (ptype in ('I','R','S')), qty number (5) FOREIGN KEY pno REFERENCES product (pno) ON DELETE CASCADE);
Determine the Three Views of Data We know that the similar thing, if viewed from dissimilar angles produces difference sights. Similarly, the database that we have formed alrea
Differentiate between logical database design and physical database design. Show how this separation leads to data independence? Basis Logical Databas
Wait-die" scheme : The idea is based on non-preventive method. It is based on a simple rule: If Ti requests a database resource that is held by T
compare the features of oracle RDBMS with MySQL and Microsoft SQL server
State the functional approach of object oriented methods Moving from a functional approach to an object oriented one needs a translation of functional model elements into objec
Give detail description on Transactions. - Using transactions we can group all SQL commands into a single unit. - Transaction begins with some task and finishes only when a
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd