What attribute can have only one value?

Single-valued Attribute Single-valued Attribute This attribute has only one value. It is represented by a simple oval. Some simple attribute can also be a single-valued attribute. For example, the Section of ‘Student’ is a simple attribute as it can’t be further divided.

What attribute is one that Cannot be subdivided?

simple attributes Attributes that cannot be subdivided are called simple attributes. First Name and Last Name are now simple attributes. Most attributes have only a single value and as such are called single valued attributes.

Is a set of possible values for a given attribute?

In computing, the attribute domain is the set of values allowed in an attribute.

When the PK of one entity does not contain the PK of a related entity the relationship is ___?

A weak or non-identifying relationship exists between two entities when the primary key of one of the related entities does not contain a primary key component of the other related entities. A strong or identifying relationship is when the primary key of the related entity contains the primary key of the “parent”.

Can attributes have attributes?

Composite attribute You can use composite attributes to contain simple attributes. You can always break a composite attribute down into two or more simple attributes (or even more composite attributes, but we’ll get into that later).

What are multi valued attributes?

A multivalued attribute of an entity is an attribute that can have more than one value associated with the key of the entity. For example, a large company could have many divisions, some of them possibly in different cities.

What is derived attribute in database?

Derived attribute − Derived attributes are the attributes that do not exist in the physical database, but their values are derived from other attributes present in the database. For example, average_salary in a department should not be saved directly in the database, instead it can be derived.

Is an attribute whose value is calculated from other attributes?

2. Derived Attribute : A derived attribute is an attribute whose values are calculated from other attributes.

Which of the following can be a multivalued attribute?

Explanation: NULL always represents that the value is not present. 8. Which of the following can be a multivalued attribute? Explanation: Name and Date_of_birth cannot hold more than 1 value.

What are the types of attributes in DBMS?

There are five such types of attributes: Simple, Composite, Single-valued, Multi-valued, and Derived attribute.

What is the difference between attribute and value?

As nouns the difference between value and attribute is that value is the quality (positive or negative) that renders something desirable or valuable while attribute is a characteristic or quality of a thing.

What is composite attribute?

Composite attribute is an attribute where the values of that attribute can be further subdivided into meaningful sub-parts. Typical examples for composite attribute are; Name – may be stored as first name, last name, middle initial.

Which of the following refers to the number of attributes in a relation?

Explanation: Cardinality refers to the number of tuples of relation because cardinality represents the number of tuples in a relation.

What is an attribute that can be further subdivided to yield additional attributes?

Composite and Simple Attributes: Attributes are classified as simple or composite. A composite attribute is an attribute that can be further subdivided to yield additional attributes.

What do entities of similar attributes?

Entities of similar type are placed in one entity set/table. Group of attributes that easily identifies a tuple forms a key. An entity can be a tangible entity or an intangible entity. Each attribute has a certain domain and it may be involved in forming a key.

What are entities and attributes?

The main difference between Entity and Attribute is that an entity is a real-world object that represents data in RDBMS while an attribute is a property that describes an entity. … It helps to store and manage data efficiently to access them easily.

What are attributes in database?

In relational databases, attributes are the describing characteristics or properties that define all items pertaining to a certain category applied to all cells of a column. The rows, instead, are called tuples, and represent data sets applied to a single entity to uniquely identify each item.

Can attributes have attributes ERD?

In ER model, entities have attributes which can be of various types like single-valued, multi-valued, composite, simple, stored, derived and complex. But relationships can also have attributes associated to them.

What is complex attribute?

complex Attribute is a type of attribute in database. … For example, A person can have many phone numbers,many e-mail addresses,home addresses etc.So if there is a attribute in the name of ‘Contact detail’,it can be a complex attribute.

What are the key attributes?

A key attribute is the unique characteristic of the entity. For ex. Name and hire date are attributes of the entity Employee.

Which attribute is the derived attribute?

Derived attribute: A derived attribute is one whose value is dynamic and derived from another attribute. It is represented by dashed oval in an ER Diagram. For example – Person age is a derived attribute as it changes over time and can be derived from another attribute (Date of birth).

What are types of attributes?

Types of Attributes-

What is required attribute in database?

A required attribute is an attribute that must have a value in it, while an optional attribute may not have a value in it and can be left blank. The reasoning for making an attribute required is to ensure that data are collected for that particular characteristic.

What is descriptive attribute?

A descriptive attribute or simply a descriptor, on the other hand, describes a non-unique characteristic of an entity instance. For example, the attributes Price and Page_count are the descriptive attributes as two books can have the same price and number of pages.

What are stored and derived attributes?

Stored attribute −Stored attributes are the attributes that exist in the physical database . For example , date_of_birth. Derived attribute − Derived attributes are the attributes that do not exist in the physical database, but their values are derived from other attributes present in the database.

What is the difference between a composite attribute and a multi valued attribute?

Most attributes are atomic attributes. Multivalued A multivalued attribute may have one or more values for a particular entity. … Composite Composite attributes are not atomic because they are assembled using some other atomic attributes.

What is derived attribute in SQL?

  1. In ER model, derived attribute is a type of attribute where the value for that attribute will be derived from one or more of the other attributes of the same entity set.
  2. Consider the following entity set for example;
  3. In this entity set Employee, Experience is a derived attribute (represented as dashed ellipse).

How are many-to-many relationships typically handled in databases?

When you need to establish a many-to-many relationship between two or more tables, the simplest way is to use a Junction Table. A Junction table in a database, also referred to as a Bridge table or Associative Table, bridges the tables together by referencing the primary keys of each data table.

Which of the following is similar to Pred value attribute?

7. Which of the following is similar to ‘PRED(value) attribute? Explanation: The value previous to the argument value is returned by the ‘PRED attribute. The same is done by ‘LEFTOF, it returns the value left to the argument which means the same as that of ‘PRED.

Which one of the following is a set of one or more attributes taken collectively to uniquely?

Which one of the following is a set of one or more attributes taken collectively to uniquely identify a record? Explanation: Super key is the superset of all the keys in a relation.