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First Normal Form and second normal form
First Normal Form (1NF)
A relation is said to be in 1NF if it having no non-atomic values and each row can give a unique combination of values.
Second Normal Form (2NF)
A relation is said to be in 2NF f if it is already in 1NF and each attribute fully depends on the primary key of the relation. Speaking inversely, if a table has some attributes which is not dependant on the primary key of that table, and then it is not in 2NF.
Example: RELATIONAL SCHEMA for PERSON: PERSON (PERSON_ID: integer, NAME: string, AGE: integer, ADDRESS: String) RELATION INSTANCE In this instance, m = 3 and n = 4
What is a value? A data value is used for identity. This form of identity is used in relational systems.eg: The primary key value of a tuple recognize the tuple.
UNION If R1 and R2 are two union compatible relations then R3 = R1 ∪ R2 is the relation having tuples that are either in R1 or in R2 or in both. In case, R3 will have tuples
Explain several types of constraints that can be specified using CREATE TABLE command. Explain CASCADE and RESTRICT clauses of DROP SCHEMA command? Constraint Description PRIM
You must implement the entity relationship model provided in the model solution to Assignment 1. The model solution will be released on the course website approximately TWO (2) we
tell me the functionality,advantages and disadvantages of student database
Define Shared locks? Ans: Shared lock: Throughout concurrent execution of transactions, earlier than a transaction can access a data item, it has to obtain a lock on it. Now he
It defines that the tuple in one relation that refers to another relation must refer to an existing tuple in that relation. This constraint is states on two relations (not essentia
Illustration of implementation of inheritance Let us take the illustration of implementation of inheritance. Suppose that we are about to implement the Stack class and by now w
Consider the 1ollowin8 relation: CAR SALE (Car_id, Option_type, Option_listprice, Sale_date, Option_discountedprice) This relation refers to options installed in cars (e.g., crui
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