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The correct choice is (d) AGGREGATION

The best I can explain: One LIMITATION of E-R model is that it cannot express relationships among relationships. Thus for this purpose, aggregation is used. Aggregation is an ABSTRACTION through which relationships are treated as higher LEVEL entities.

The CORRECT option is (a) ATTRIBUTE defined

Best explanation: CONDITION defined generalization constraint is also SAID to be attribute defined.

Correct answer is (d) MACHINE defined

The explanation is: Machine definition is not a generalization CONSTRAINT. CONDITION defined, USER defined, disjoint and OVERLAPPING are 4 generalization constraints.

Right option is (a) TRUE

For explanation: The ATTRIBUTES of the higher level ENTITY sets are INHERITED by the attributes of the lower level entity sets. But the inverse is not true in this case.

Right option is (b) SUPER CLASS

Easiest explanation: Higher level entity sets can ALSO be designated by the TERM super class. In the similar manner lower level entity sets can also be designated by the term sub class.

Correct choice is (b) Generalization

Explanation: The similarities between the ENTITY set can be EXPRESSED by the generalization feature. It is a containment o the relationship that exists between a HIGHER LEVEL entity set and one or more lower level entity sets.

Right ANSWER is (c) Overlapping specialization

Explanation: Overlapping specialization is the TYPE of specialization that permits MULTIPLE sets. But DISJOINT specialization does not permit multiple sets. Disjoint specialization permits at most ONE set.

The correct OPTION is (a) True

The EXPLANATION: We can apply specialization multiple TIMES to REFINE a design. An ENTITY set may also be specialized by more than one distinguishing feature.

The correct choice is (c) Statement 1 is true and Statement 2 is false

The best explanation: We can create foreign key constraints on relational schema derived from ER diagram and ALSO it is POSSIBLE to derive relational schema from ER DIAGRAMS.

The CORRECT ANSWER is (a) True

To elaborate: The schema for the RELATIONSHIP SET linking a weak entity set to its CORRESPONDING strong entity set is redundant and it need not be present in the relational database design derived from an ER diagram.

The correct OPTION is (c) UNION of primary keys

To elaborate: For a binary MANY to many relationship, the union of the primary keys of the PARTICIPATING entity SETS becomes the prime attribute.

The correct OPTION is (d) Primary key on the many side

For explanation I WOULD SAY: For a binary many to many relationship, the primary key on the many side of the participating ENTITY sets becomes the prime attribute.

Right CHOICE is (b) PRIMARY key of either one

Easiest explanation: For a BINARY one to one relationship, the primary key of either one of the participating ENTITY SETS becomes the prime attribute.

Correct option is (c) Union of primary keys

To EXPLAIN: For a binary many to many relationship, the union of the primary keys of the participating ENTITY sets becomes the PRIME ATTRIBUTE.

Right choice is (a) Discriminator of the weak ENTITY set

The best I can explain: The PRIMARY key of the REPRESENTATION of a weak entity set consists of the primary key of the STRONG entity set and the discriminator of the weak entity set.

The correct ANSWER is (a) True

For explanation: DERIVED attributes cannot be DIRECTLY represented in the RELATIONAL data model. Instead, they are represented as methods.

Correct choice is (b) Primary key

To elaborate: For schemas derived from STRONG entity sets, the primary key of the entity SET SERVES as the primary key of the resulting schema. This is because the primary KEYS are to be preserved as they are unique.

Right choice is (B) False

The BEST EXPLANATION: It cannot PARTICIPATE in all the RELATIONSHIPS. A weak entity set can only participate in relationships other than the identifying relationship.

The correct OPTION is (a) True

Easiest EXPLANATION: Every weak entity SET must be ASSOCIATED with an IDENTIFYING entity. The weak entity is then said to be existence dependent on the identifying entity set.

Correct choice is (a) Identifying relationship

The best EXPLANATION: The relationship associating the WEAK entity SETS with the identifying entity set is called as an Identifying relationship. An identifying set is a many to ONE from the weak entity set to the identifying entity set.

The CORRECT option is (a) STRONG entity set

Easy EXPLANATION: An entity set that has a primary key is called as a strong entity set. An entity set that does not have a primary key is called a WEAK entity set.

The correct answer is (C) USING a dashed line

Best explanation: A DISCRIMINATOR of a WEAK entity set can be specified by underlining it with a dashed line.

The CORRECT choice is (a) One-one

Explanation: A directed LINE ( →)from a relationship SET to two ENTITY SETS means that there is a one-one cardinality between two entity sets.

The CORRECT ANSWER is (c) Relationship SETS linked to weak ENTITY sets

Explanation: The double diamonds represent the relationship sets linked to weak entity sets. Weak entity sets are the sets that do not have a primary KEY.

Right option is (b) Diamonds

Explanation: Diamonds REPRESENT RELATIONSHIP sets in an ER diagram. Relationship sets define how two ENTITY sets are RELATED in a database.

Correct CHOICE is (a) Divided RECTANGLES

Easy explanation: Rectangles divided into two parts REPRESENT entity SETS in an ER diagram. The upper rectangle contains the NAME of the entity sets. And the lower rectangle contains the attributes.

The correct ANSWER is (b) Removing redundant attributes

The EXPLANATION: Removing redundant attributes from a relation makes DATA extraction more efficient and faster. Thus, it is a good DATABASE management TECHNIQUE.

The correct choice is (b) TOTAL

Easiest EXPLANATION: Let E be an entity SET in a relationship set R. If every entity in E participates in at least one RELATION in R, Then the participation of E in R is total.

The CORRECT answer is (B) They are those attributes which can further be divided into other attributes

To EXPLAIN: Composite attributes are the ones which can be further divided into other attributes WHEREAS SIMPLE attributes cannot be divided into other attributes.

The correct ANSWER is (C) DESCRIPTIVE

To elaborate: A RELATIONSHIP may also have attributes. These attributes are CALLED as descriptive attributes.

Correct CHOICE is (a) Extension

Easy explanation: The extension of the entity SET is an actual COLLECTION of ENTITIES belonging to that entity set.