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Data warehousing has become an integral part of most organizations today, and one area that has seen a significant amount of growth in data warehousing is Human Resources (HR). In this blog post, we will discuss the concept of dimensional modeling and how it can be effectively used in designing HR data warehouses. We'll be looking at technologies such as SQL Server 2016, SQL Server 2017, MySQL 5.7, DB2 11.1 and Azure SQL.

Dimensional modeling is a technique used in data warehouse design that aims to improve the readability and performance of the database by using a logical design. It involves the use of a fact table surrounded by dimension tables. The fact table contains the business data, and the dimension tables contain the context of the business data. In the context of HR, the fact table could contain data about employee performance, while the dimension tables could contain information about the employees, their departments, and their roles.

Let’s consider an example using SQL Server 2017 where we create a simple HR data warehouse. The fact table could be 'EmployeePerformance' and the dimension tables could be 'Employee', 'Department' and 'Role'.

CREATE TABLE EmployeePerformance (
  PerformanceID int,
  EmployeeID int,
  DepartmentID int,
  RoleID int,
  PerformanceMetric float
)


CREATE TABLE Employee (
  EmployeeID int,
  EmployeeName varchar(50),
  EmployeeDOB datetime
)


CREATE TABLE Department (
  DepartmentID int,
  DepartmentName varchar(50)
)


CREATE TABLE Role (
  RoleID int,
  RoleName varchar(50)
)

In the MySQL 5.7, the same structure can be achieved using similar syntax.

CREATE TABLE EmployeePerformance (
  PerformanceID INT,
  EmployeeID INT,
  DepartmentID INT,
  RoleID INT,
  PerformanceMetric FLOAT
);


CREATE TABLE Employee (
  EmployeeID INT,
  EmployeeName VARCHAR(50),
  EmployeeDOB DATE
);


CREATE TABLE Department (
  DepartmentID INT,
  DepartmentName VARCHAR(50)
);


CREATE TABLE Role (
  RoleID INT,
  RoleName VARCHAR(50)
);

Now, let's consider DB2 11.1. Here, the same data warehouse structure would look as follows.

CREATE TABLE EmployeePerformance (
  PerformanceID INTEGER,
  EmployeeID INTEGER,
  DepartmentID INTEGER,
  RoleID INTEGER,
  PerformanceMetric REAL
);


CREATE TABLE Employee (
  EmployeeID INTEGER,
  EmployeeName VARCHAR(50),
  EmployeeDOB DATE
);


CREATE TABLE Department (
  DepartmentID INTEGER,
  DepartmentName VARCHAR(50)
);


CREATE TABLE Role (
  RoleID INTEGER,
  RoleName VARCHAR(50)
);

Azure SQL provides a cloud-based solution for data warehouse design, but the syntax is very similar to SQL Server. Therefore, the same structure can be created in Azure SQL as in SQL Server.

In conclusion, dimensional modeling is a powerful technique for designing HR data warehouses. It provides a logical and efficient structure for storing and querying data, making it easier for HR professionals to access and analyze their data. Whether you're using SQL Server 2016, SQL Server 2017, MySQL 5.7, DB2 11.1 or Azure SQL, understanding how to apply dimensional modeling to your HR data warehouse design can greatly enhance your HR data management and analytics capabilities.