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!
Define entity integrity and referential integrity. How does SQL allow specification of these?
Ans: Entity Integrity Rule- If the attribute A of relation R is a prime attribute of R after that A cannot accept null values.
Referential Integrity Rule- In referential integrity, it is made sure that a value that appears in one relation for a given set of attributes as well appears for a particular set of attributes in another relation.
In SQL, referential integrity and entity integrity rules are implemented as constraints on the relation known as reference Key constraint and primary Key constraint correspondingly.
These constraints can be fixed with relation at the time of creation of the relations or after the creation of the relations by altering the definition of the relations. For instance:
What is nested relational model? The nested relational model is an extension of relational model in which domains might be either atomic or relation valued.
Order by clause By using this rows can be sorted It is used in the last portion of select statement By default it gets ascending order DESC: is used
#questiontypes of keys examples..
what are the states of transaction?
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
What is Natural Language Interfaces? Natural Language Interfaces - These interfaces accept requests written within English or a few other language and attempt to "understand" t
1. Will you advise that your organization uses open source software and why? 2. Why is it important for business managers to have a basic understanding of the software development
List some instances of collection types? a) sets b) arrays c) multisets
triggering
What is object identity? An object retains its identity even if some or all the values of variables or explanations of methods change overtime.
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