Can An Entity Have Two Relationships With Another Entity?


There can be a number of between the same two entities

. For example: Employee is assigned to a Project, … One entity can participate in a number of different involving different entities.

Can an entity be connected to another entity?

In a many-many relationship,

an entity of either set can be connected to many entities of the other set

. E.g., a bar sells many beers; a beer is sold by many bars. one from one entity set to another. Each entity of the first set is connected to at most one entity of the second set.

How many relationships can an entity have?

This is how a relationship between two tables is established. There are

three types of relationships

that can exist between two entities.

Can a weak entity have two relationships?

‘Can a weak entity be related to another weak entity’ I would say No. A weak entity has no primary key of its own but does have a foreign key which is linked to the PK of another entity. Thus if you have two weak entities with the same FK id they are

infact related to the same strong entity rather than each other

.

What is it called when two entity set participating in a one relationship?

When there is only ONE entity set participating in a relation, the relationship is called as . For example, one person is married to only one person. 2.



– When there are TWO entities set participating in a relation, the relationship is called as binary relationship.

Can an entity have a relationship with itself?


It is possible for an entity to have a relationship

with itself; for example, an entity Staff could have a relationship with itself, as one member of staff could supervise other staff. This is known as a recursive or involute relationship, and would be represented in an entity-relationship diagram as shown below.

What are the 4 types of relationships?

There are four basic types of relationships:

family relationships, friendships, acquaintanceships, and romantic relationships

. Other more nuanced types of relationships might include , teacher/student relationships, and community or group relationships.

How do you identify relationships between entities?

Identifying relationships exist

when the primary key of the parent entity is included in the primary key of the child entity

. On the other hand, a non-identifying relationship exists when the primary key of the parent entity is included in the child entity but not as part of the child entity’s primary key.

How do you identify relationships and entities?

Identifying relationships exist

when the primary key of the parent entity is included in the primary key of the child entity

. On the other hand, a non-identifying relationship exists when the primary key of the parent entity is included in the child entity but not as part of the child entity’s primary key.

What is the participation of a weak entity in a relationship?

A weak entity always has a

total participation constraint with respect to its identifying relationship

because it cannot be identified independently of its owner identity.

How do you identify attributes of entities?

Entities contain attributes , which are characteristics or modifiers, qualities, amounts, or features. An attribute is a fact or nondecomposable piece of information about an entity. Later, when you represent an entity as a table, its attributes are added to the

model

as new columns.

What is Entity Relationship Diagram?

An entity relationship diagram (ERD), also known as an entity relationship model, is

a graphical representation that depicts relationships among people, objects, places, concepts or events

within an information technology (IT) system.

What does double rectangles show in entity relationship diagram?

An entity that cannot be uniquely identified by its own attributes and relies on the relationship with other entity is called

weak entity

. The weak entity is represented by a double rectangle.

Can an entity have 1 attribute?


Yes

, but. If an entity only has one attribute, then that attribute must serve as an identifier for the entity. Typically, if only one attribute is found for an entity in the given data stream, then another attribute is “invented” for purposes of identifying.

Can a weak entity have no attributes?


Does not have sufficient attributes to form a primary key

. Depends on the strong entity set it is associated with. Needs a discriminator and a primary key of the strong entity set.

What Type Of Ternary Relationship Cannot Be Depicted As Two Binary Relationships?

What type of CANNOT be depicted as two binary ?

A

can have one or many maximum cardinalities on either side. A unique attribute is an attribute whose value is different for each entity instance.

How many entities are involved in a binary relationship?

The , an association between

two entities

, is by far the most common type in the natural world.

What is depicted by relational schema?

A relational schema is a

visual depiction of the relational database model

. Two columns of a relational table can have the same names. Two columns of a relational table can have the same values.

What is the difference between a unary relationship and a ternary relationship quizlet?

A unary relationship means the degree of the relationship is one, while a ternary relationship means the

degree of the relationship is three

. … A unary relationship means the degree of the relationship is three, while a ternary relationship means the degree of the relationship is one.

Which of the following attributes is defined as having at most a single value for any given entity instance?

By definition,

a simple attribute

is an attribute that cannot be divided in simpler parts that have a different semantic meaning in the real world. A single-value attribute has at most a value for any given entity instance.

Why a ternary relationship is not the same as three binary relationships?

If a ternary relationship is represented instead with 3 , there are,

for each endpoint of a relationship

(there are six of them) 4 possibilities (single or multiple, tutal or partial), so in total one can have 24 possible combinations, that this a number of possible specifications which is the …

What is a ternary relationship How is it represented in ERD?

In Ternary relationship

three different Entities takes part in a Relationship

. Relationship Degree = 3. For Example: Consider a Mobile manufacture company. Three different entities involved: Mobile – Manufactured by company.

What is binary relationship in database?

A Binary Relationship is

the relationship between two different Entities

i.e. it is a relationship of role group of one entity with the role group of another entity. There are three types of cardinalities for Binary Relationships − 1. One-to-One.

Which of the following is not a type of database?

Answer:

folder database

is not a type of database.

Which of the following is not a process of generating a good relational schema?

Which of the following is not a process of generating a good relational schema? Explanation:

Joining multiple relations together to form a single relation containing all the attributes

is not a method for the development of good relational schema because it might violate the normal forms if it is combined.

What is a dependent entity?

Data points or entities that may only exist or have certain values if a certain requirement is met by another entity. In a many to many relationship, dependent entities are

created to simplify data models

. For example, many buildings may have many rooms, but each room can only be in one building.

How does intersection data relate to an associative entity?

How does intersection data relate to an associative entity?

An entity that has two or more primary keys derived from the entities that form the intersection of the attributes associated with the original entities

.

Can a ternary relationship have intersection data explain?

Ternary relationships can have intersection data to

describe the combination of one occurrence in each of the three entities

. … Ternary relationships can have intersection data to describe the combination of one occurrence in each of the three entities.

What is the problem associated with having two or more multi valued attributes?

Question: What is the problem with multivalued attributes? Multivalued attributes can cause

problems with the meaning of data in the database

, significantly slow down searching, and place unnecessary restrictions on the amount of data that can be stored.

What are the different types of relationships in DBMS?

  • One-to-One Relationship.
  • One-to-Many or Many-to-One Relationship.
  • Many-to-Many Relationship.

What kind of attribute would be date of birth?

Date of birth would be

a stored attribute

. A one-to-many relationship occurs between two entities in which an instance of one entity can be related to only one instance of a related entity.

Can an entity have 2 relationships?


There can be a number of between the same two entities

. For example: Employee is assigned to a Project, … One entity can participate in a number of different relationships involving different entities.

What is binary relationship and ternary relationship?

Binary Relationship: a binary relationship is

a relationship of degree two

. That is the relationship contains two participating entities. It can take the form of 1:1, 1:M, or M:N. Ternary Relationship: a ternary relationship is a relationship of degree three.

What is binary relationship and ternary relationship why we need to use ternary relationship?

The binary recursive relationship construct is a diamond with both connections to the same entity. A ternary relationship is an association among three entities. This type of relationship is required

when binary relationships are not sufficient to accurately describe the semantics of the association

.

What is the difference between binary and ternary relationship in database?

A binary relationship is when two entities participate and is the most common relationship degree. A unary relationship is when both participants in the relationship are the same entity. For Example: … A ternary relationship is when

three entities participate

in the relationship.

What are the types of relationship?

There are four basic types of relationships:

family relationships, friendships, acquaintanceships, and romantic relationships

. Other more nuanced types of relationships might include , teacher/student relationships, and community or group relationships.

What is ternary relationship in DBMS?

In the Ternary relationship, there are three types of entity associates. So, we can say that a Ternary relationship exists

when there are three types of entity and we call them a degree of relationship is

3. Since the number of entities increases due to this, it becomes very complex to turn E-R into a relational table.

What are the different types of constraints on binary relationships?

We can distinguish two main types of binary relationship constraints:

cardinality ratio and participation

. Cardinality Ratios for Binary Relationships. The cardinality ratio for a binary relationship specifies the maximum number of relationship instances that an entity can participate in.

What is binary relationship example?

We can also use to trace relationships between people or between any other objects. Examples of binary relations between people:

Family relations

(like “brother” or “sister-brother” relations), the relation “is the same age as”, the relation “lives in the same city as”, etc.

How do you read a ternary relationship?

Assume the ternary relationship has participating entities A, B and C (for degree > 3 it gets pretty hairy). The way to read the relationship is

to always isolate 2 out of the 3 participating entities and see how they relate towards the third one

. And you need to do this for all possible pairs.

Which of the following is not a relational database?

2) Non-relational databases, also called NoSQL databases, the most popular being

MongoDB

, DocumentDB, Cassandra, Coachbase, HBase, Redis, and Neo4j. These databases are usually grouped into four categories: Key-value stores, Graph stores, Column stores, and Document stores (see Types of NoSQL databases).

Which of the following is not a feature of a good relational design?

1. Which of the following is not a feature of a good relational design? Explanation:

Allowing redundancy of attributes makes it very difficult for data extraction

. So, It is not a good relational design feature.

Which of the following is not considered as a logical structure of the database?


è Chain

is not a logical database structure to represent the data logically.

Which of the following is not an aggregate function?

Which of the following is not an aggregate function? Explanation:

With is used to create temporary relation

and its not an aggregate function.

Which of the following is not a example of relational database?


Spreadsheet

is not the example of relational database.

Which of the following is not a database software?

The correct answer is

MS word

. MS Word since it’s a word processor. Microsoft Word is a word processor developed by Microsoft.

What is ternary relation in discrete mathematics?

In mathematics, a or triadic relation is

a finitary relation in which the number of places in the relation is three

. Ternary relations may also be referred to as 3-adic, 3-ary, 3-dimensional, or 3-place.

Which of these are used to express relationship among relationship?

Explanation:

An ERD

can also be referred as Entity Relationship Model. It is actually a graphical representation which is used for depicting the relationships among the objects, people, concepts, places or any kinds of events within an IT environment.

How ternary associations are mapped to the tables in database?

Each of the

3 entities

and the association between them gets stored in its own database table. … It follows the same concept as the association table of a many-to-many association. It contains the 3 foreign keys of the associated entities and uses all 3 of them as its derived primary key.

What is the difference between an identifying and non identifying relationship?

Identifying relationships exist when the primary key of the parent entity is included in the primary key of the child entity. On the other hand, a non-identifying relationship exists when the primary key

of the parent entity is included in the child entity but not as part of the

child entity’s primary key.

Which is not included in the definition of an entity?

4. Which is NOT included in the definition of an entity? answer:

Action

An entity is a person, place, object, event, or concept. … answer: STUDENT_ID STUDENT_ID depends upon the existence of the STUDENT entity, so it is not a strong entity type.

What is an entity that can serve as the relationship between other entities called?

Entities that exist to represent the relationship between two or more other entities are known as

composite entities

.

Which type of relation requires an associative table?

An associative entity is a term used in relational and entity–relationship theory. A relational database requires the implementation of

a base relation (or base table)

to resolve many-to-many relationships. A base relation representing this kind of entity is called, informally, an associative table.

What is a composite associative entity and when is it used?

Associative (Composite) Entities:

The associative entity is used

to implement a M:N relationship between two or more entities

. This associative entity (also known as a composite or bridge entity) is composed of the primary keys of each of the entities to be connected.

When must a many-to-many relationship be Modelled as an associative entity?

2 Answers. Associative entities are used when you need a relationship to

be involved

in a relationship. For a normal many-to-many relationship between Student and Course , we would use just a diamond. However, if we want to associate Enrollment with Teacher , we can turn Enrollment into an associative entity.

Which type of relationship is not allowed in a relational database?

Relational Database Database Stored data can be accessed from the relational database because there is a relationship between the tables and their attributes. There is no relationship between data value or tables stored in files.

What does does not allow an attribute value to be multivalued?


Only one value at the intersection of a column and row

: A relation does not allow multivalued attributes. Uniqueness: There are no duplicate rows in a relation. A primary key: A primary key is a column or combination of columns with a value that uniquely identifies each row.

Which of the following Cannot be used to modify the data in a database?

Explanation:

The drop keyword is used to delete

the entire relation leaving no trace of it in the memory. Thus it cannot be used to edit the data in the relation.

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