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Cours

Hierarchical and Recursive Queries in SQL Server

AvancéNiveau de compétence

Actualisé 03/2023

Learn how to write recursive queries and query hierarchical data structures.

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SQLProgramming4 h13 vidéos47 Exercices3,800 XP12,558Certificat de réussite.

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Description du cours

Do you want to query complex data structures in an iterative way? Do you have access to hierarchical data structures that need to be queried? This course will teach you the tools required to solve these questions. You will learn how to write recursive queries and query hierarchical data structures. To do this, you will use Common Table Expressions (CTE) and the recursion principle on a wide variety of datasets. You will, for example, dig into a flight plan dataset and learn how to find the best and cheapest connection between two airports. After completing this course, you will understand the principle of recursion, and be able to identify and create hierarchical data models.

Prérequis

Functions for Manipulating Data in SQL Server

1

Recursion and Common Table Expression (CTE)

In this chapter, you will learn about recursion and why it is beneficial to apply this technique. You will also refresh your knowledge about Common Expression Tables (CTE).

Recap of Common Table Expressions (CTE)

What is a CTE?

A CTE for IT-positions

A CTE for high-paid IT-positions

Introduction to recursion

Facts about recursion

Calculate the factorial of 5

How to query the factorial of 6 recursively

Solve recursive maths problems

Counting numbers recursively

Calculate the sum of potencies

Commencer Le Chapitre

2

Hierarchical and Recursive Queries

In this chapter, you will learn about recursive CTEs, how to query hierarchical datasets, and finally, how to apply recursive CTEs on hierarchical data.

Introduction to recursive CTE

Right or wrong?

Create the alphabet recursively

Create a time series of a year

Working with recursive queries

Who is your manager?

Get the hierarchy position

Which supervisor do I have?

Analyze the family tree

Get the number of generations?

Get all possible parents in one field?

Commencer Le Chapitre

3

Creating Data Models on Your Own

In this chapter, you will learn how to create and modify database tables. You will learn about relational and hierarchical data models, how they differ, and when each model should be used.

How to work with tables

Creating a table

Inserting and updating a table

Deleting data and dropping table

Changing a table structure

Working with relational data models

Defining primary and foreign keys

Inserting data to person and order history

Getting the number of orders & total costs

Working with hierarchical data models

Creating a hierarchical data model

Networked and hierarchical models

Creating a networked data model

Commencer Le Chapitre

4

Hierarchical Queries of Real-World Examples

In this chapter, you will practice your learnings about hierarchical and recursive querying on real-world problems, such as finding possible flight routes, assembling a car, and modeling a power grid.

Travel planning for flight data

Get the anchor & recursive member

Get all possible airports

All flight routes from Vienna

How to assemble a car?

Create the parts list

Create a car's bill of material

Build up a BMW?

Modeling a power grid

Create a power grid

Get power lines to maintain

Summary of the course

Commencer Le Chapitre

Hierarchical and Recursive Queries in SQL Server

Cours
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