Table of Contents
- 1 What is a weak entity explain with example?
- 2 What is a weak entity and what two conditions must be met before an entity can be classified as a weak entity Give an example of a weak entity?
- 3 How do you represent a weak entity?
- 4 What is a weak relationship provide an example quizlet?
- 5 Could you have an example of a weak entity?
- 6 What is weak entity types?
What is a weak entity explain with example?
In a relational database, a weak entity is an entity that cannot be uniquely identified by its attributes alone; therefore, it must use a foreign key in conjunction with its attributes to create a primary key. There are two types of weak entities: associative entities and subtype entities.
What are strong entities and weak entities?
The Key Difference between Strong and Weak Entity is that a Strong Entity has a primary key whereas a Weak Entity does not have a primary key. Weak entity is dependent on a strong entity whereas a Strong entity is independent not dependent on any other.
What is a weak entity and what two conditions must be met before an entity can be classified as a weak entity Give an example of a weak entity?
In any case, two conditions must be met before an entity can be classified as weak: 1. The entity must be existence-dependent on its parent entity 2. The entity must inherit at least part of its primary key from its parent entity.
How can I make my weak entity strong?
Though weak entity set can be converted into strong entity set by simply adding appropriate attributes, this approach results in the redundant storage of primary key. ii. The primary key of a weak entity set can be inferred from its relationship with the strong entity set.
How do you represent a weak entity?
Weak entity is represented by double rectangle. The relation between one strong and one weak entity is represented by double diamond. Weak entities are represented with double rectangular box in the ER Diagram and the identifying relationships are represented with double diamond.
How do you identify a weak entity?
What is a weak relationship provide an example quizlet?
Provide an example. A weak relationship, also known as a non-identifying relationship, exists if the primary key of the related entity does not contain a primary key component of the parent entity. In this example, the CLASS primary key did not inherit a primary key component from the COURSE entity.
How weak entity can be connected to strong entity explain with an example?
The relationship of two strong entities is represented by a single diamond….Difference between Strong and Weak Entity:
S.NO | Strong Entity | Weak Entity |
---|---|---|
1. | Strong entity always has a primary key. | While a weak entity has a partial discriminator key. |
3. | Strong entity is represented by a single rectangle. | Weak entity is represented by a double rectangle. |
Could you have an example of a weak entity?
A classic example of a weak entity without a sub-type relationship would be the “header/detail’ records in many real world situations such as claims, orders and invoices, where the header captures information common across all forms and the detail captures information specific to individual items.
What is the difference between strong and weak entity?
Key Differences Between Strong Entity and Weak Entity The basic difference between strong entity and a weak entity is that the strong entity has a primary key whereas, a weak entity has the partial key which acts as a discriminator between the entities of a weak entity set.
What is weak entity types?
There are two types of weak entities: associative entities and subtype entities . The latter represents a crucial type of normalization, where the super-type entity inherits its attributes to subtype entities based on the value of the discriminator.
What is a weak entity set?
Weak Entity Sets. An entity set that does not have a primary key is referred to as a weak entity set. The existance of a weak entity set depends on the existence of a strong entity set; it must relate to the strong set via a on-to-many relationship set.