Lesson 1: Converting a Table to a Hierarchical Structure

Customers who have tables using self joins to express hierarchical relationships can convert

their tables to a hierarchical structure using this lesson as a guide. It’s relatively easy to migrate

from this representation to one using. After migration, users will have a compact

and easy to understand hierarchical representation, which can be indexed in several ways for

efficient queries.

This lesson examines an existing table, creates a new table containing a

column,

populates the table with the data from the source table, and then demonstrates three indexing

strategies. This lesson contains the following topics:

To complete this tutorial, you need SQL Server Management Studio, access to a server that’s

running SQL Server, and an AdventureWorks database.

Install

Management Studio.

Install

2022 Developer Edition.

Download

AdventureWorks sample databases.

For instructions on restoring databases in SSMS, see

Restore a Database Backup Using SSMS.

The sample

database contains an

table in the

schema. To avoid changing the original table, this step makes a copy of the

table

named. To simplify the example, you only copy five columns from the original

table. Then, you query the

table to review how the data is

structured in a table without using the

data type.

In a Query Editor window, run the following code to copy the table structure and data from the

table into a new table named. Since the original table already uses

AdventureWorks2025
Employee
HumanResources
Employee
EmployeeDemo
HumanResources.EmployeeDemo
Employee
EmployeeDemo