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 the difference between SQL Server 2000 clustered and nonclustered indexes? With a clustered index, the data are kept in the bottom level of the index and in the similar
What is the difference between a HAVING CLAUSE and a WHERE CLAUSE? HAVING CLAUSE - HAVING CLAUSE is used only with SELECT statement. - It is normally used in a GROUP BY
1. Create the tables for the play-scheme database as specified in the TMA. 2. Enter the data as given in the spreadsheet. 3. Create queries to retrieve specified information
What is Object Oriented model? This model is based on collection of objects. An object has values stored in instance variables with in the object. An object also having bodies
What is a foreign key, and what is it used for? A foreign key is used to establish relationships between relations in the relational model. Technically, a foreign key is a colu
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.
What are the ways in which the variable-length records arise in database systems? Storage of many record types in a file. Record types that permit variable lengths for one o
Problem : AirwaysCentre, an international airline booking company currently uses a relational database system for their operations, which includes the following relations: P
Mention the several levels in security measures. A) Database system B) Operating system C) Network D) Physical Human
Define the five basic operators of relational algebra? Five basic operators of relational algebra are: 1. Union (∪∪∪∪) - Selects tuples which are in either P or Q or in both
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