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).
What is meant by heuristic optimisation?Discuss the major heuristics that are applied during query optimisation.
Define database management system? Database management system (DBMS) is a set of interrelated data and a combination of programs to access those data.
Q. Describe how an ER schema can be represented by relation schemas and constraints arising from ER design can be mapped to constraints on a relation schema. The entity rela
Differentiate between Primary and secondary storage? Primary and secondary storage - Primary storage device stores the data temporarily. Primary storage is commonly used thro
Wait-die" scheme : The idea is based on non-preventive method. It is based on a simple rule: If Ti requests a database resource that is held by T
Need 2 projects completed in 3NF format.
Control Files : The redo and control files logs support the rest of the architecture. Every database must have at least one control file, although you have more than one to guard
Information about films holds information about movies, stars and studios. Movies have a title, year of production, length and the film type. Stars have a name and address. Studi
Explain Alternate key? Alternate Key - All the candidate keys except primary key are known as alternate keys.
Explain the systems development life cycle. This is the traditional method to develop, maintain, and replace information systems that contains the project identification and se
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