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!
When are two schedules said to be view equivalent?
Ans: Two schedules that is denoted as S and S' are said to be view equivalent if the subsequent three conditions are met
1) For every data item Q, if a transaction Ti reads the initial value of Q in schedule S, after that transaction Ti should in schedule S' also read the initial value of Q.
2) For every data item Q, if a transaction Ti executes read(Q) in schedule S and that value was generated by Tj (if any) , then transaction Ti must in schedule S' as well read the value of Q generated by Tj.
3) For every data item Q, if a transaction if any that carries out the final write(Q) in schedule S should perform the final write(Q) in schedule S'.
Example : Create a sequence named SEQSS that starts at 105, has a step of 1 and can take maximum value as 2000. CREATE SEQUENCE SEQSS START WITH 105 INCREMENT BY 1 MAX VA
How many levels can be viewed in Architecture of the database ? Architecture of the database can be viewed as three levels.
real life situations where database management system are most suitable
Describe an data dictionary? A data dictionary is a data structure which keeps meta data about the structure of the database ie. the schema of the database.
Describe multi key files
Identification of concurrency Identification of concurrency: Dynamic model identifies concurrency. Two objects are said to be parallel (concurrent) if they can receive events a
The Database Approach In order to overcome the limits of a file system, a new approach was needed. Hence a database approach emerged. A database is a persistent collection of
What are the purpose for having variable length records? What kinds of separator characters are required for each? Variable-Length Records - Variable-length records are thos
Mention the type of constraints we can specify in the CREATE command of DDL. The type of constraints that can be specified are as follows:- PRIMARY KEY, NOT NULL, UNIQUE, FOR
Explain forms based and graphical interface? Forms based and graphical interface: graphical user interface (GUI) is a kind of user interface which permits people to interact
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