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!
Explain Two phase locking protocol
A transaction is consider as to follow the two-phase locking protocol if all locking operations precede the first unlock operation in the transaction. Such type of transaction can be divided into two phases: and expanding or growing (first) phase, throughout which new locks on items can be acquired but none can be released; and a shrinking (second) phase, throughout which existing locks can be released but no new locks can be obtained. This two-phase protocol can make sure the serializability because all the data items needed by a transaction will be locked at the starting of the transaction and if other transaction needs to use those data items then it has to wait till they become unlocked.
why are older data models are being replaced by new data models
What is horizontal fragmentation? Horizontal fragmentation divides the relation by assuming every tuple of r to one or more fragments
What is inheritance? Inheritance is an object orientation concept that allows reusability of code / design. Basic sense of inheritance is that if one class is predefined than a
Australian Bureau of Statistics (ABS) provides retail data for different groups and different states as well as the aggregate numbers. Table 11 " Retail Turnover, State by Industry
What are domain constraints? A domain is a set of values that might be assigned to an attribute .all values that appear in a column of a relation must be taken fro
Cardinality of Relationship One-to-One Only one entity of the first set is linked to only one entity of the second set. E.g. A teacher teaches a student. Only one teacher
Differentiate between static hashing and dynamic hashing. Ans: Static Hashing comprises the number of primary pages in the directory fixed. So, while a bucket is full, we requ
Column Constraints: NOT NULL, UNIQUE, CHECK, PRIMARY KEY, DEFAULT, REFERENCES, On delete Cascade : Using this key whenever a parent row is removed in a referenced
Examples:- Hierarchical Model: It tells data as and relationships by hierarchy of data values. Figure illustrates an example of hierarchical model. Now a day's these models are
Consider the following relations: BRANCH( bno, street, area, city, pcode, Tel_no, Fax_no) STAFF( Sno, Fname, Lname, address, position , salary, bno) Express the subsequent qu
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