for student and course number what is relationship

Full Answer

What is the relationship between a student and a course?

A relationship between a students and courses can be considered as many to many, where The Entities are students and courses and the Relationship is enroll. This means, if you put this information in a DBMS table, a multiple rows of one table associates itself with multiple rows of another table.

What is the many-to-many relationship between student and course tables?

For example, the Student and Course tables have many-to-many relationship that is defined by one-to-many relationship from each of these tables to the Enrollment table. The following code contains the Course class and the above two classes, i.e., Student and Enrollment.

How to find the number of courses taken by a student?

That is handled via a course_id column in the Sections table. Many Students take many Courses. "Many-to-many". That is handled by a many:many table with two columns: course_id and section_id. Note that you can find the course_id from the Sections table. Facilty:Sections is also many:many.

What is a relationship in a level math example?

A relationship describes how entities interact. For example, the entity “Carpenter” may be related to the entity “table” by the relationship “builds” or “makes”. Relationships are represented by diamond shapes and are labeled using verbs.

What is the relationship between student and course?

A student and a course are entities, while an enrollment is a relationship between a student and a course. Similarly, an inventory and sales database might store information about products, customers, and sales. A product and a customer are entities, while a sale is a relationship between a customer and a product.

What do you mean by many-to-many relationship between teacher and student entity?

Many-to-Many Relationship It means one Student can enroll for many Courses and also, one Course can be taught to many Students. The database includes the StudentCourse joining table which includes the primary key of both the tables ( Student and Course tables).

What do you mean by many-to-many relationship between class and student table?

A typical example of a many-to many relationship is one between students and classes. A student can register for many classes, and a class can include many students. The following example includes a Students table, which contains a record for each student, and a Classes table, which contains a record for each class.

What is the relationship between course and section?

Each section is uniquely identified by a section number. Not every course will be offered in a semester and some courses may have multiple offerings (multiple sections of the course). A student can enrolled in one section of some course. A student can enrolled in multiple sections in one semester.

What do you mean by one-to-many relationship between class and student?

One student can have many classes. Many classes may have many student.

What do you mean by one-to-many relationship between teacher and course table?

Answer: Explanation: In a "class roster" database, a teacher may teach zero or more classes, while a class is taught by one (and only one) teacher. This kind of relationship is known as one-to-many. ... The one-to-many relationship cannot be represented in a single table.

What is a relationship what is a one-to-many relationship?

What Does One-to-Many Relationship Mean? In relational databases, a one-to-many relationship occurs when a parent record in one table can potentially reference several child records in another table.

What is an example of a one-to-many relationship?

Some common examples of one-to-many relationships are: A car maker makes many different models, but a particular car model is built only by a single car maker. One customer may make several purchases, but each purchase is made by a single customer.

What type of relationship exists between a teacher table and class table?

one-to-manyThis kind of relationship is known as one-to-many. The one-to-many relationship cannot be represented in a single table. For example, in a "class roster" database, we may begin with a table called Teachers, which stores information about teachers (such as name, office, phone, and email).

What is a course section number in college?

The five-digit section number denotes the day, time, location and instructor teaching the course. This five digit number and all pertinent information attached to a section number is set by the department of the course.

What is the relationship between faculty and course?

Courses are assigned to faculty members and students are enrolled in courses. System will show courses and their instructors(faculty members) to each student which he or she has to study and faculty members will see record of all students of a particular section which he or she has to teach.

What does course mean in school?

A course is a series of classes. These classes are all in one area of study. Therefore, when choosing a major, you will take courses geared towards that major. Courses are assigned credits. Colleges dictate how many credits you need to take to graduate.

What is the degree of a relationship?

Degree of a Relationship. The degree of a relationship is the "number of entities" associated with the relationship. The n-ary relationship is the general form for degree n. Special cases are the binary, and ternary forms, where the degree is 2, and 3, respectively. In a binary relationship, the association between two entities represents ...

Why is classname inserted into student?

ClassName attribute is inserted into STUDENT as well, in order to identify the classes in which a student is enrolled (not just through cryptic ClassID, but by ClassName as well).

What is the relationship between connectivity and cardinality?

Connectivity and Cardinality. The connectivity of a relationship describes the mapping of associated entity instances in the relationship. The values of connectivity are "one" or "many". The cardinality of a relationship is the actual number of related occurences for each of the two entities.

When to use ternary relationships?

A ternary relationship involves three entities and is used when a binary relationship is not sufficient to represent your modeling scenario. Many modeling approaches recognize only binary relationships. When ternary or n-ary relationships are present in a data modeling use case, they are decomposed into two or more binary relationships.

What are the types of connectivity?

The basic types of connectivity for relations are: 1) one-to-one, 2) one-to-many, and 3) many-to-many. A one-to-one (1:1) relationship is when at most one instance of a entity A is associated with one instance of entity B. For example, "employees in the company are each assigned their own office.

Can students and classes be linked?

Student Class Entities. The STUDENT and CLASS entities cannot actually be put into a direct relationship, because this is forbidden in a relational database. However, assume for the moment that they are directly related in the following fashion: The ClassID (key attribute) from CLASS is inserted into STUDENT to form the link.

Can many to many relationships be directly translated to relational tables?

Many-to-many relationships cannot be directly translated to relational tables but instead must be transformed into two or more one-to-many relationships using associative entities. In conceptual modeling you can combine any of the cardinality choices on either side of the relationship.

Can a course have many sections?

One Course can have many Sections. "One-to-many". That is handled via a course_id column in the Sections table.

Is it good to have two tables in a one to one relationship?

I don't know where you are going with "OneToOneField". Generally it is not good to have two tables in a one-to-one relationship.

What is a relationship between a student and a university?

A relationship between a Students and University can be considered as one to one, where The Entities are Students and University and the Relationship is study. This means, if you put this information in a DBMS table, multiple rows of student table associates itselves with single row of University table.

What is a relationship between a company and employees?

A relationship between a Company (1) and Employees (n) can be considered as one to many, where The Entities are company and employees and the Relationship is pays . This means, if you put this information in a DBMS table, a particular row of one table associates itself with multiple rows of another table.

Is a relationship between a husband and wife one to one?

A relationship between a husband and wife can be considered as one to one, where The Entities are Husband and Wife and the Relationship is Marriage This means, if you put this information in a DBMS table, a particular row of one table only associates itself with single and unique row of another table.

What is a recursive relationship?

Recursive Relationship. If the same entity participates more than once in a relationship it is known as a recursive relationship . In the below example an employee can be a supervisor and be supervised, so there is a recursive relationship. Example of a recursive relationship in ER diagrams.

What is a relationship in a diagram?

A relationship describes how entities interact. For example, the entity “Carpenter” may be related to the entity “table” by the relationship “builds” or “makes”. Relationships are represented by diamond shapes and are labeled using verbs. Using Relationships in Entity Relationship Diagrams.

How to draw an ER diagram?

How to Draw ER Diagrams 1 Identify all the entities in the system. An entity should appear only once in a particular diagram. Create rectangles for all entities and name them properly. 2 Identify relationships between entities. Connect them using a line and add a diamond in the middle describing the relationship. 3 Add attributes for entities. Give meaningful attribute names so they can be understood easily.

What is an attribute in ER?

An attribute is a property, trait, or characteristic of an entity, relationship, or another attribute. For example, the attribute Inventory Item Name is an attribute of the entity Inventory Item. An entity can have as many attributes as necessary. Meanwhile, attributes can also have their own specific attributes. For example, the attribute “customer address” can have the attributes number, street, city, and state. These are called composite attributes. Note that some top level ER diagrams do not show attributes for the sake of simplicity. In those that do, however, attributes are represented by oval shapes.

What are the elements of an ER diagram?

There are three basic elements in an ER Diagram: entity, attribute, relationship. There are more elements which are based on the main elements. They are weak entity, multi valued attribute, derived attribute, weak relationship, and recursive relationship. Cardinality and ordinality are two other notations used in ER diagrams to further define ...

What is it called when an attribute has more than one value?

If an attribute can have more than one value it is called a multi-valued attribute . It is important to note that this is different from an attribute having its own attributes. For example, a teacher entity can have multiple subject values.

Why use ER diagrams?

This means that designers can use ER diagrams to easily communicate with developers, customers, and end users, regardless of their IT proficiency.

How many types of relationships are there between tables?

There are three types of relationships between tables and the relationship between different tables depends on how the related columns are defined. One-to-Many Relationship. Many-to-Many Relationship. One-to-One Relationship.

What is the most common type of relationship?

A one-to-many relationship is the most common type of relationship.

What is a relational database?

In relational databases, relationship is a situation that exists between relational database tables through foreign keys. A Foreign Key (FK) is a column or combination of columns that is used to establish and enforce a link between the data in two tables. The following diagram contains three tables.

What is the primary key of a junction table?

You can create such a relationship by defining a third table, called a junction table, whose primary key consists of the foreign keys from both table A and table B.

Which class has collections of enrollment objects?

You can see that both Course class and Student class have collections of Enrollment objects which makes many-to-many relationship via junction class Enrollment.

Does enrollment class have a single object?

In the above code, you can see that Student class contains the collection of Enrollment, but Enrollment class has a single Student Object.