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 the two constraints, check and foreign key in SQL along with an example for each. Give the syntax.
CHECK constraint - CHECK constraint specifies an expression which must always be true for every row in the table. It can't refer to values within other rows.Syntax:ALTER TABLE ADD CONSTRAINT CHECK();
FOREIGN KEY constraint - A foreign key is a combination of columns along with values based on the primary key values from another table. A foreign key constraint, also called as referential integrity constraint, specifies in which the values of the foreign key correspond to actual values of the primary or unique key in other table. One can refer to a primary or unique key in the similar table also.
Syntax: ALTER TABLE ADD CONSTRAINT FOREIGN KEY()REFERENCES () ON {DELETE | UPDATE}CASCADE;
Describe Physical Data independence ? Physical Data Independence - It is capacity to modify the internal schema without having to change conceptual schema. Therefore, the exter
Insertion Anomaly: Inability to show certain information-The primary key of the over relation be (enrolment number, Cno). Any new tuple to be inserted in the relation should have
Give some encryption techniques? A) DES B) AES C) Public key encryption
Given the following set of functional dependencies {cf?bg, g?d, cdg?f, b?de, d?c} defined on R(b,c,d,e,f,g) a.Find a non-redundant cover. b.Find a canonical cover.
Question 1 Suppose the employee employee id, name, designation, salary, attendance and address of any employee has to be stored in a database. You can store these data in a sequen
How does Tuple-oriented relational calculus vary from domain-oriented relational calculus? The tuple-oriented calculus uses a tuple variables i.e., variable whose only allowed
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
Explain Data Dictionary in short?
Write short notes on domain relational calculus The domain relational calculus uses domain variables that take on values from an attribute domain rather than values for whole t
What is a virtual table that draws its data from the result of an SQL SELECT statement? View is a virtual table that draws its data from the result of an SQL SELECT statement.
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