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Worked Examples
We will use the data shown in the ERD above, with tables for Buildings, Rooms, Bookings, Staff, Departments and Certificates.
Accessing Attributes
- If you have a booking, you can access the department name and building name
Aggregating on Attributes
- Aggregation: Get the number of bookings for a department name
Multi-Hop Worked Examples
In this example, we will explore how data can be accessed across different tables even where the tables do not have a direct relationship. This is called multi-hop and PhixFlow supports multi-hop relationships to a distance of 4 hops. In the below examples we will use the School Data from the Learning Centre, containing tables for Students, Attendees, Courses, Teachers, Departments and Classrooms.
ERD Setup
Example 1: Show Course Details
We want to see the details for each course, including its classroom, students and teacher. This involves 2 hops between the Courses and Students tables.
- On the ERD, click on the Courses table header to open the table configuration
- In the Properties, in the Views section, create a new view
- Name:
CourseDetails
- Save the View
- Name:
- In the View Attributes section, click the
iconInsert excerpt _attributes_icon _attributes_icon nopanel true - In the Available Attributes window:
- From the Courses table, drag across the CourseID and Name attributes into the View Attributes section of the View
- Under Related Tables, select the Classrooms table
- Drag across the ClassroomID and Name attributes into the View Attributes section of the View
- Under Related Tables, click back onto the Courses table, then onto the Attendees table (this allows us to hop to the Attendee's related tables), then onto the Students table
- Drag across the StudentID and Name attribute into the View Attributes section of the View
- Click back onto the Courses table using the link above the attribute selector
- Then click onto the Teachers table under Related Tables
- Drag across the TeacherID and Name attribute into the View Attributes section of the View
- Drag across the TeacherID and Name attribute into the View Attributes section of the View
- Optionally, set a Default Sort Order on the view
- Display the data in the View by hovering over
and clickingInsert excerpt _more_options _more_options nopanel true
DisplayInsert excerpt _view_show_icononly _view_show_icononly nopanel true
Example 2: Show Courses Attended By Female Students
We want to see all courses attended by female students. This involves 2 hops between the Courses and Students tables.
- On the ERD, click on the Courses table header to open the table configuration
- In the Properties, in the Views section, create a new view
- Name:
StudentsOnCourses
- Save the View
- Name:
- In the View Attributes section, click the
iconInsert excerpt _attributes_icon _attributes_icon nopanel true - In the Available Attributes window:
- From the Courses table, drag across the CourseID and Name attributes into the View Attributes section of the View
- Under Related Tables, select the Attendees table - this allows us to hop to the Attendee's related tables
- Drag across the StudentID attribute into the View Attributes section of the View
- Under Related Tables, select the Students table
- Drag across the Name and Gender attribute into the View Attributes section of the View
- Drag across the Name and Gender attribute into the View Attributes section of the View
- In the Data Retrieval Options on the View, create a new Default Filter
- Filter: create a new filter
- Name:
FemalesOnly
- Filter Details:
Gender
equalsFemale
- Name:
- Filter: create a new filter
- Optionally, set a Default Sort Order on the view
- Display the data in the View by hovering over
and clickingInsert excerpt _more_options _more_options nopanel true
DisplayInsert excerpt _view_show_icononly _view_show_icononly nopanel true
Example 3: Quantity of Males vs Females on Each Course
This example uses aggregation. We want to see the number of male and female students taking each course. This involves 2 hops between the Courses and Students data.
- On the ERD, click on the Course table header to open the table configuration
- In the Properties, in the Views section, create a new view
- Name:
CourseByGender
- Save the View
- Name:
- In the View Attributes section, click the
iconInsert excerpt _attributes_icon _attributes_icon nopanel true - In the Available Attributes window:
- From the Course table, drag across the CourseID and Name attributes into the View Attributes section of the View
- Under Related Tables, select the Attendees table - this allows us to hop to the Attendee's related tables
- Under Related Tables, select the Students table
- Drag across the Gender attribute twice into the View Attributes section of the View
- Double click on one of the Schools_StudentsGender attributes
- On the View Attributes properties:
- Name:
Males
- Aggregate Function: choose
Count
- Filter: create a new filter
- Name:
ByMales
- Filter Details:
Gender
equalsMale
- Name:
- Name:
- On the View Attributes properties:
- Repeat these steps for the other Schools_StudentsGender attribute but this time for Females
- Optionally, set a Default Sort Order on the view
- Display the data in the View by hovering over
and clickingInsert excerpt _more_options _more_options nopanel true
DisplayInsert excerpt _view_show_icononly _view_show_icononly nopanel true
Example 4: Quantity of Courses in Each Department
This example uses aggregation. We want to see how many courses are in each department.
- On the ERD, click on the Department table header to open the table configuration
- In the Properties, in the Views section, create a new view
- Name:
CoursesCount
- Save the View
- Name:
- In the View Attributes section, click the
iconInsert excerpt _attributes_icon _attributes_icon nopanel true - In the Available Attributes window:
- From the Department table, drag across the Name attribute into the View Attributes section of the View
- To access the Courses table, under Related Tables, select either the Teachers table or Classrooms table
- Under Related Tables, select the Courses table
- Drag across the CourseID attribute into the View Attributes section of the View
- Double click on the CourseID attribute
- On the View Attributes properties:
- Name:
CourseCount
- Aggregate Function: choose
Count
- Name:
- On the View Attributes properties:
- Optionally, set a Default Sort Order on the view
- Display the data in the View by hovering over
and clickingInsert excerpt _more_options _more_options nopanel true
DisplayInsert excerpt _view_show_icononly _view_show_icononly nopanel true
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Example IdeasCourses with the most students? How many males do maths level 1 how many students are on a course see all males and females on maths level 1 since 2021 Students on Each Course: We want to see the number of males and females on each course. Students and Teachers in a Department: We want to see the names of teachers and students on each course.
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