7.4. Explain The Difference Between An Attribute And A Value Set
7.4. What is an entity type? What is an entity set? Explain the differences among an entity, an entity type, and an entity set.
Entity:
An entity is a thing or object in the real world. An object may be with a physical existence or with a conceptual existence. A set of these entities having same attributes is entity type and collection of individual entity type is an entity set.
Entity type:
A set of entities that have the same attributes is called an entity type. Each and every entity type in the database is described by a name and a list of attributes. Entity type defines a collection of entities that have the same attributes.
For example an entity employee is an entity type that has Name, Age and Salary as attributes.
Entity set:
It is …show more content…
It may be tangible or intangible. Examples of an entity are employees or any physical object.
Entity type describes the schema or intension for a set of entities that share the same structure.
Entity set is the extension of the entity type and a collection of related data.
7.5. Explain the difference between an attribute and a value set.
Attribute:
An attribute is a particular property that describes entity. A value set specifies the set of values that may be assigned to that attribute for each individual entry. An example of an attribute is and
An attribute is a property that describes a real entity. Now for all entities there are certain values that each attribute can take. Set of all values that an attribute can take is called value set. Often the value that attribute take are lesser in number than number of element in value set.
Difference between an attribute and value set can simply be taken as that between a variable and group of values that this variable can take. For example for a person an attribute can be name such as Employee Age. For value of this attribute we can set the value set to a range of integer …show more content…
It has its origins in Object Oriented programming languages (OOPL). In today’s time OO concepts are applied in the areas of databases, software engineering, artificial intelligence, computer systems and have their roots in the SIMULA language, which was proposed in the late 1960s. The Smalltalk programming language developed at Xerox PARC8 in the 1970’s, was one of the first languages to explicitly incorporate additional OO concepts, such as message passing and inheritance. It is known as a pure OO programming language. An object typically has two components: state (value) and behavior (operations). The object can have a complex data structure as well as specific operations defined by the programmer, objects in an OOPL only exist during program execution and they are called transient objects. OO databases store persistent objects permanently in secondary storage, and allow the sharing of these objects among multiple programs and applications. Object-oriented systems allow definition of the operations or functions (behavior) that can be applied to objects of a particular
Entity:
An entity is a thing or object in the real world. An object may be with a physical existence or with a conceptual existence. A set of these entities having same attributes is entity type and collection of individual entity type is an entity set.
Entity type:
A set of entities that have the same attributes is called an entity type. Each and every entity type in the database is described by a name and a list of attributes. Entity type defines a collection of entities that have the same attributes.
For example an entity employee is an entity type that has Name, Age and Salary as attributes.
Entity set:
It is …show more content…
It may be tangible or intangible. Examples of an entity are employees or any physical object.
Entity type describes the schema or intension for a set of entities that share the same structure.
Entity set is the extension of the entity type and a collection of related data.
7.5. Explain the difference between an attribute and a value set.
Attribute:
An attribute is a particular property that describes entity. A value set specifies the set of values that may be assigned to that attribute for each individual entry. An example of an attribute is and
An attribute is a property that describes a real entity. Now for all entities there are certain values that each attribute can take. Set of all values that an attribute can take is called value set. Often the value that attribute take are lesser in number than number of element in value set.
Difference between an attribute and value set can simply be taken as that between a variable and group of values that this variable can take. For example for a person an attribute can be name such as Employee Age. For value of this attribute we can set the value set to a range of integer …show more content…
It has its origins in Object Oriented programming languages (OOPL). In today’s time OO concepts are applied in the areas of databases, software engineering, artificial intelligence, computer systems and have their roots in the SIMULA language, which was proposed in the late 1960s. The Smalltalk programming language developed at Xerox PARC8 in the 1970’s, was one of the first languages to explicitly incorporate additional OO concepts, such as message passing and inheritance. It is known as a pure OO programming language. An object typically has two components: state (value) and behavior (operations). The object can have a complex data structure as well as specific operations defined by the programmer, objects in an OOPL only exist during program execution and they are called transient objects. OO databases store persistent objects permanently in secondary storage, and allow the sharing of these objects among multiple programs and applications. Object-oriented systems allow definition of the operations or functions (behavior) that can be applied to objects of a particular