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.
Logical Operators Rules of Precedence: Order evaluated Operator 1 All comparison operators 2
wh
What are the several forms of identity? a) Value b) Name c) Built-in
Explain the Aggregation implies concurrency Concurrency actually is: This in objects can be identified by the way they change state. Present objects can change state independen
Produce a set of relations (equivalent to the Finkelstein entity list) in third normal form (3NF) from the following un-normalised relation. You must use the Finkelstein methodolog
Mappings between Levels and Data Independence The 3 levels of abstraction in the database do not exist separately of each other. There must be some correspondence, or mapping
Concatenation operator Example : Printing name and job as one string as column name employees: SELECT ENAME||JOB "EMPLOYEES" FROM EMP;
# ???? ..
Define the Canonical cover Ans: A canonical cover F c for F is a set of dependencies like F logically implies all dependencies in F c , and F c logically entails all dependen
Which is another name for weak entity? Child is another name of weak entity.
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