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What is weak entity sets in dbms?
An entity set may not have sufficient attributes to form a primary key is called weak entity set. One with primary key is called strong entity set.
When is the concept of weak entity used in data modelling?
A weak entity can be identified uniquely only by considering the primary key of another (owner) entity.
Were the beam briges strong or weak?
They WERE weak, which is why they are in the past tense. They are all gone because they fell apart. They sucked.
What is the disadvantage of lap winding?
It is always strong quite weak
What are the key differences between strong and weak AI in terms of their capabilities and potential impact on society?
Strong AI, also known as artificial general intelligence, possesses human-like cognitive abilities and can perform a wide range of tasks independently. Weak AI, on the other hand, is designed for specific tasks and lacks general intelligence. Strong AI has the potential to revolutionize society by enabling advancements in various fields, while weak AI is limited in its scope and impact.
What is weak entity sets in dbms?
An entity set may not have sufficient attributes to form a primary key is called weak entity set. One with primary key is called strong entity set.
Why do we need weak entity sets?
why do we need weak entity in database when we can make it strong entity?
Can weak entity be converted into strong entity?
The primary key of a weak entity set is formed by taking the primary key of the strong entity set on which its existence depends (see Mapping Constraints) plus its discriminator. A strong entity set has a primary key. All tuples in the set are distinguishable by that key. A weak entity set has no primary key unless attributes of the strong entity set on which it depends are included. Tuples (a particular row) in a weak entity set are partitioned according to their relationship with tuples in a strong entity set. Tuples within each partition are distinguishable by a discriminator, which is a set of attributes.
What is strong and weak entity set?
the enitity which is set primary key is said to be strong entity and the entity which does not set primary key is said to be weak entity.
What is strong entities vs weak entities?
The table that has primary key is strong entity and the table that has no primary key is weak entity
How can you convert weak entity to strong entity?
To convert a weak entity to a strong entity, you can assign it a primary key that uniquely identifies each instance of the weak entity, rather than relying on the primary key of its associated strong entity. This often involves creating a new attribute or a combination of attributes within the weak entity itself to serve as the primary key. Additionally, you may need to remove the dependency on the strong entity's key, ensuring the weak entity can exist independently. Lastly, update the database schema to reflect these changes.
Explain the difference between a weak and a strong entity set?
An entity set that does not possess sufficient attributes to form a primary key is called a weak entity set. One that does have a primary key is called a strong entity set. The discriminator (or partial key) of a weak entity set is the set of attributes that distinguishes among all the entities of a weak entity set The existence of a weak entity set depends on the existence of a identifying entity set. It must relate to the identifying entity set via a total, one-to-many relationship set from the identifying to the weak entity set We depict a weak entity set by double rectangles in E-R diagram. We underline the discriminator of a weak entity set with a dashed line in E-R diagram.
What occurs when a weak entity does not have a candidate key and its instances are indistinguishable without a relationship with another entity?
When a weak entity lacks a candidate key and its instances cannot be uniquely identified without a relationship to another entity, it relies on that relationship to establish its identity. This typically occurs in a one-to-many relationship where the weak entity’s existence is dependent on the strong entity, which provides the necessary identifying attributes. As a result, the weak entity will often include a foreign key from the related strong entity as part of its primary key. Without this relationship, instances of the weak entity would be indistinguishable and cannot be adequately represented in the database.
What is the difference between a regular and a weak and a regular entity?
A regular entity, also known as a strong entity, has a primary key that uniquely identifies each instance and can exist independently of other entities. In contrast, a weak entity does not have a sufficient primary key and relies on a "strong" or "regular" entity for its identification; it is dependent on the strong entity for its existence and typically has a partial key. Weak entities are often used to represent a relationship that requires more context, while regular entities stand alone as distinct objects in a database.
What two conditions must be met before an entity can be classified as a weak entity?
In contrast to the strong or regular entity, a weak entity is one that meets two conditions: 1. The entity is existence-dependent; that is, it cannot exist without the entity with which it has a relationship. 2. The entity has a primary key that is partially or totally derived from the parent entity in the relationship.
What is the difference between a required attributes and optional attributes?
strong entity : in this the attributes must have values for instance . weak entity : in this the attributes may or may not have values for instance .
How do you convert weak entities to relations?
To convert weak entities to relations in a database schema, you first need to identify the weak entity's identifying relationship with its owner entity. This involves including a foreign key in the weak entity that references the primary key of the owner entity. Additionally, the weak entity should have its own primary key, typically created by combining its partial key with the primary key of the owner entity. Finally, this new relation can be established in the relational schema, ensuring that the weak entity can now be uniquely identified.
