Found 1719 Articles for Big Data Analytics

ProblemDraw an ER model of the Banking database application considering the following constraints −A bank has many entities.Each customer has multiple accounts.Multiple customers belong to a single branch.Single customer can borrow multiple loans.A branch has multiple employees.SolutionFollow the steps given below to draw an ER model of the Banking database application −Step 1 − Identify the entity setsThe entity set has multiple instances in a given business scenario.As per the given constraints the entity sets are as follows −CustomerAccountAccountLoanLoanStep 2 − Identify the attributes for the given entitiesCustomer − the relevant attributes are customerName, CustomerID, address.Account − The relevant attributes ... Read More

ProblemDrawing of ER model of university database application considering the constraints −A university has many departments.Each department has multiple instructors (one person is HOD). Here the HOD refers to the head of department.An instructor belongs to only one department.Each department offers multiple courses, each subject is taught by a single instructor.A student may enroll for many courses offered by different departments.SolutionFollow the steps given below to draw an Entity Relationship (ER) diagram for a University database application −Step 1 − Identifying the entity sets.The entity set has multiple instances in a given business scenario.As per the given constraints the entity ... Read More

It is the relationship between the instances of two different entity types. Two entities will participate in the relationship.ExamplePerson and events are two different entity types which are related by using the relationship called “attends”.Mapping ER diagram with binary relationshipMapping one to many relationshipExampleHere, Create two tables for two entities.Primary key of one side relation is a foreign key for many side relations.One side relation is customer and many side relations is Order.The primary key cutomerID of the customer is a foreign key of order.The equivalent relations for the above ER diagram are as follows −One-one, many-one, many-many can be ... Read More

The attributes that cannot be divided into sub-parts are called simple attributes. The attributes which can be divided into sub-parts are called composite attributes.ExampleBalance, account number are simple attributesName, address is called composite attributesLet’s consider an example of how to convert Entity Relationship (ER) model of composite attribute to Relational model.Methods for mappingName of relation = Entity set of ER diagramName of column = Attribute of ER diagramExampleIn this example, Name of the relation =studentName of columns=StdID, name, BranchThe equivalent relation for the above ER diagram is −StudentStdIDNameBranchNow apply this technique for Mapping ER diagram with a composite attribute as ... Read More

Key is a data item which is used to identify a record or a value used to identify a record in a database is called a key. It helps uniquely to identify an entity from an entity set.Key allows us to identify a set of attributes that make them sufficient to distinguish entities from each other.ExampleAccount number, employee number, customer number are used as a key field because they specifically identify a record stored in a database.Foreign KeyIn a relation, the column whose data values correspond to the values of a key column in another relation is called a foreign ... Read More

Key is a data item which is used to identify a record or a value used to identify a record in a database is called a key. It helps uniquely to identify an entity from an entity set.Key allows us to identify a set of attributes that make them sufficient to distinguish entities from each other.ExampleAccount number, employee number, customer number are used as key fields because they specifically identify a record stored in a database.Different types of keysThe different types of keys in the database management system (DBMS) are as follows −Primary keySuper keyCandidate keyAlternate keyArtificial keyForeign keyPrimary, super, ... Read More

Key is a data item which is used to identify a record or a value used to identify a record in a database is called a key. It helps uniquely to identify an entity from an entity set.Key allows us to identify a set of attributes that make it sufficient to distinguish entities from each other.ExampleAccount number, employee number, customer number are used as key fields because they specifically identify a record stored in a database.Different types of keysThe different types of keys in the database management system (DBMS) are as follows −Primary keySuper keyCandidate keyAlternate keyArtificial keyForeign keyPrimary, super, ... Read More

ER-Diagram is a pictorial representation of data which describes how the data is communicated and related to one another. Any object, like entities, attributes of an entity, sets of relationship and other attributes of relationship are characterized with the help of the ER diagram.E-R Diagram ComponentsThe Entity Relationship (ER) diagram components are as follows −E-R Design DecisionsThe use of an attribute or entity set generally represents an object. To check a real-world concept it is best expressed by an entity set or a relationship set. The use of any ternary relationship versus a pair of binary relationships occurs in the ... Read More

The number of entity types which took part in the entity relationship is called the degree of relationships.There are three different types of degree of relationships, they are as follows −Unary relationshipBinary relationshipTernary relationshipUnary relationshipIt is the relationship between the instances of a single entity type. It is also called a recursive relationship.ExampleA person is married is a one-to-one relationship between the instances of Person entity type of unary relationship.Binary relationshipIt is the relationship between the instances of two different entity types. Two entities will participate in the relationship.For ExamplePerson and events are two different entity types which are related ... Read More

Extended ER is a high-level data model that incorporates the extensions to the original ER model. Enhanced ER models are high level models that represent the requirements and complexities of complex databases.The extended Entity Relationship (ER) models are three types as given below −AggregationSpecializationGeneralizationSpecializationThe process of designing sub groupings within an entity set is called specialization. It is a top-down process. If an entity set is given with all the attributes in which the instances of the entity set are differentiated according to the given attribute value, then that sub-classes or the sub-entity sets can be formed from the given ... Read More