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What else can I help you with?
What is difference between object and entity?
A database object is represented as one of the following: database, schema, table, column, primary key, and foreign key A database Entity is: An entity is a thing or object of importance about which data must be captured. All things aren't entities - only those about which information should be captured. Information about an entity is captured in the form of attributes and/or relationships. If something is a candidate for being an entity and it has no attributes or relationships, it isn't an entity. Database entities appear in a data model as a box with a title. The title is the name of the entity.
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.
What is peer entity?
In layered systems, one of a set of entities that are in the same layer or the equivalent layer of another system.
What do you understand by table relationship in database design?
A table relationship is where a field in one table is matched with the same field in another table. For example you may have a table that lists your suppliers so 'Supplier Name' is one of the fields, you may then have another table that lists orders made so "Supplier Name" will be a field in that table also. Therefore you can link the two tables together so that all specific supplier address details are linked to subsequent orders with that supplier. For a relationship to work both linking fields must be of the same data type, therefore you can't link a field that is stated as text with one that is stated as a date. Relationships are commonly known as one-to-one and one-to-many, in a one-to-one relationship the field's contents can only appear once on each side so using the example above one supplier in the suppliers table can only have one order record in the orders table. "One to many" therefore means that one supplier can appear on many orders. Hope this helps.
Entity relationship diagram of hr system?
In case you have no background in computer science, entity relationship is a method that conceptually identifies the interacting, and independent objects( both physical and otherwise) in an information system with the view to avoid data redundancy, maintain data integrity, improve data efficiency, increase resource utilization in terms of storage management and access speed or system response time. Pls let stop here. An instance of your diagram, which I will stress you little, is to quickly image 1. A hostel and rooms in it, here Hostel as well as the rooms are treated as different entities. 2. imagine manager and employee under him in an organization, even though they can all be referred to as employees yet manager is different entity In a nut shell we use a line to link two interacting entities and the cardinality( which is to be discuss professionally as either one to one, one to many). That is all. I am not too good at drawing but I could conceptualize it mentally. If this does not satisfy you do not hesitate to mail me at: maduchudi@yahoo.com I will always be for you all.
What are 10 cardinalities appropriate for ERD?
In an Entity-Relationship Diagram (ERD), cardinalities define the relationships between entities. Common cardinalities include: One-to-One (1:1) - Each entity in set A is related to one entity in set B and vice versa. One-to-Many (1:N) - An entity in set A can relate to multiple entities in set B, but an entity in set B relates to only one in set A. Many-to-One (N:1) - Multiple entities in set A can relate to one entity in set B. Many-to-Many (M:N) - Entities in set A can relate to multiple entities in set B and vice versa. Zero or One (0..1) - An entity may or may not have a relationship with another entity. Zero or Many (0..N) - An entity can have no relationship or many relationships with another entity. Exactly One (1) - An entity must have exactly one relationship with another entity. At Least One (1..N) - An entity must have at least one relationship but can have many. At Most One (0..1) - An entity can have no relationship or one relationship, but not more. Optional (0..M) - An entity may have zero or more relationships with another entity. These cardinalities help in modeling the data structure and understanding the interactions between different entities.
When do you have to use an intersection entity in database?
If you have a many-to-many relationship between two entities you create an intermediate entity between.Now, the relationship between the first entity and intersection entity is one-to-many, and the relationship between the second entity and intersection entity is one-to-many also.
What is democratic relationship?
a democratic relationship is one that each person is participating equally....
What is a democratic relationship?
a democratic relationship is one that each person is participating equally....
What is one to one relationship?
There are three types of relationship in a database . One to one, one to many and many to many , Example of many to many relationship is relation between teachers and students, n teachers can have m students.
When the PK of one entity does not contain the PK of a related entity the relationship is?
When the primary key (PK) of one entity does not contain the primary key of a related entity, the relationship is typically a "one-to-many" or "many-to-many" relationship. In this scenario, the primary key of the first entity can exist independently of the second entity, indicating that multiple instances of the related entity can correspond to a single instance of the first entity. This structure allows for more flexible data modeling where entities can be associated without strict dependency on each other's primary keys.
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 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.
Can an identifying relationship of a weak entity type will be of a degree greater than two give example?
Sure thing, honey. An identifying relationship of a weak entity type can definitely have a degree greater than two. For example, let's say we have a weak entity type called "Order Item" that depends on both "Order" and "Product" entities to uniquely identify it. In this case, the identifying relationship would have a degree of two (connecting "Order" and "Product") but the weak entity type itself would have a degree of three. Hope that clears things up for ya!
What is total participation in database management?
Participation (or optionality) concerns the involvement of entities i a relationship. Participation is about exceptions to the rule. An entity's participation is optional if there is a least one instance of an entity which does not participate in the relationship. An entity participation is mandatory if all instances of an entity must participate in the relationship.
What is a one-to-many relationship?
It is a term from computer databases. A relational database can have a one-to-many relationship in its data. For example, if you have a customer order database, one table will contain customer names and another will contain their orders. Each customer will only be listed once, but each customer can make many orders. So one customer can be related to many orders. Incorporating that into a database requires the creation of a one to many relationship.
What type of relationship is it called when only one thing benefits?
A relationship where only one party benefits while the other party does not gain any advantage is called a "parasitic relationship." In this type of relationship, the benefiting entity, often referred to as the parasite, exploits the other, known as the host, for resources or support. This dynamic can occur in various contexts, including biological ecosystems, social interactions, or economic exchanges.
