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 several types of constraints that can be specified using CREATE TABLE command. Explain CASCADE and RESTRICT clauses of DROP SCHEMA command?Constraint DescriptionPRIMARY KEY Determines that column(s) uniquely identifies each record. The primary key cannot be NULL, and the data value(s) must be unique.
FOREIGN KEY In a one-to-many relationship, the constraint is added to the "many" table. The constraint ensures which if a value is entered into a specified column, it must already exist in the "one" table, or the record is not added.
UNIQUE Ensures that all data values stored in a specified column are unique.The UNIQUE constraint differs from the PRIMARY KEY constraint in which it permits NULL values.CHECK Ensures in which a specified condition is true before the data value is added to a table. For example, an order's ship date cannot be previous than its order date.
NOT NULL Ensures in which a specified column cannon contain a NULL value. The NOT NULL constraint can just be created along with the column-level approach to table creation.
Prevents the DROP from taking place if any dependent objects exists (RESTRICT) or causes all dependent objects do also be dropped (CASCADE).
can you please explain with the help of suitable example the difference between conflict equivalence and conflict serializability?
Explain the ISA relationship Answer: ISA relationship - ISA notation is employed in generalization/ specialization to depict relationship among lower and higer level entity s
What are views? Explain how views are different from tables? A view in SQL terminology is a one table in which is derived from other tables. These other tables could be base t
Prepare a gantt chart for the stock control project: Scenario Lucas-TVS is the Leader in Auto Electricals in India today with 50 years experience in desig
Question: Using the data model express the following queries in SQL. (a) Create the Table named "Cinema" and make the cinema_code to be the primary key of the relation and
Use inheritance as an implementation technique when you are going to use inheritance as an implementation technique, you can achieve same goal in a safer way by making one cla
To do the division operation R1 ÷ R2, R2 should be a correct subset of R1. In the following example R1 have attributes A and B and R2 have only attribute B so R2 is a correct subse
triggering
Define Physical and Logical independence Ans: Physical data independence: The ability to modify physical level without causing application program to be rewritten. Logic
Discuss along with examples about several types of attributes present in the ER model? Types of Attributes are: • SIMPLE attributes are attributes which are drawn from the ato
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: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd