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!
This constraint shows that the key attribute value in each tuple must be unique, i.e., no two tuples have the similar value for the key attribute. This is because the value of the primary key is used to recognize the tuples in the relation.
Example: If A is the key attribute in the following relation R than A1, A2 and A3 must be unique.
A
B
A1
B1
A3
B2
A2
Example: In relation PERSON, PERSON_ID is primary key so PERSON_ID cannot be given as the similar for two persons.
Integrity Constraint
There are two kinds of integrity constraints:
Explain CNT in the respects of QBE ? CNT: It is one of the aggregation commands given in QBE. It is used to identify number of tuples
Determine the OBJECTIVES of object design After passing through this unit, you should be able to: describe and apply concept of generalisation; understand and appl
Surgeons identified by doctor ID (DOCID) operate on patients identified by patient ID (PATID) in operating theaters identified by room numbers (ROOMNO). Each surgeon can operate on
#floating point representation is used to store
Security And Integrity After Reading the concepts of database recovery in the last section, let us now deal with a vital concept that helps in minimizing consistency errors in
composite attribute
crete a data base relationship model Entity: Students; Professors; Dormitories buildings; Attributes of students: Name; Address; Dorm;
1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict
What is relational model feature? A relational model feature is much more data independence than some other database models.
File Organisation And Its Types Just as arrays, trees, lists and other data structures are used to execute data Organisation in main memory, a number of planning's are used to
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