PLEASE ASAP ts Normat Medium.. Heading 1 Heding2 Headng 3 Ttle Subtr Paragraph H

Question

PLEASE ASAP

ts Normat Medium.. Heading 1 Heding2 Headng 3 Ttle Subtr Paragraph Heath Connect had implement i, and thay have akeady been tokd this is eallypoor design. This is what thelr relational model looks Ike, with some sample data Styles an intern who prototyped a former version of the database, but they could never Mentors 8754 4579 3279 3279 3279 78 Mr Robot Robot Robot Robot Connections 8754 4579 3345 3345 3279 Ms Robot Jon Snow 8754 Adele Mickey Mouse 8754 Adele Mickey Mouse 4579 on Snow lnesses 3345 I DB01 CF22 79 HD11 For each of the 3 relations propesed (Mentors, Connections. IBnesses) explain which normal form (ONF INF or 2NF H in and why

Explanation / Answer

Since we need to distinguish each relation into 0NF or 1NF or 2NF, let’s understand first about these normal forms one by one.

In DBMS normalization technique is used to reduce the redundancy and dependency of a relation (table). To do so we have various database normal available such as 1NF, 2NF, 3NF BCNF etc.

0NF: If a column has multiple values in a relation then that relation comes under 0NF.

1NF: A relation is in 1NF if it follows below conditions:

a)       Each cell in a table must have single value.

b)      Each record of the table must be unique.

2NF: A relation is in 2NF, if it follows below conditions:

a)       Relation should be in 1NF.

b)      No partial dependency should exist in relation.

Partial dependency: No prime attribute is functionally dependant on part of candidate key. For example: XY->A where XY together forms a key and A is non-prime attribute. Non-prime means it does not belong to any key.

So partial dependency could be X->A where A is non-prime attribute and X is part of candidate key.

Now, lets discuss questions:

1: In mentors relation, no cell contain multiple values and each record of table is unique so it is 1NF.

2: In connections relation, field From ID and From name and To ID together forms a candidate key. Since ToID->ToName (partial dependency) exist so this relation cannot be in 2NF, where To Name is non prime attribute and ToID is part of candidate key.

Result: Connections table is in 1NF, since each table records are unique, and no cell contain multiple values.

3: In table illnesses, column illnesses contain multiple values, so it is in 0NF.

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.