Demystifying Data Modeling: From Concepts to Implementation
Tags: database, datamodeling, datascience, kimbal
Published: 2023-10-25 14:20:21

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## Introduction.

### What is data modeling?
Data modeling is the act of developing a visual representation of an entire information system or sections of it in order to communicate linkages between data points and structures. It entails examining and describing all of the numerous data kinds that your company gathers and generates, as well as the relationships between those bits of data.
Data modeling is an essential component of data management and system design. It entails developing a conceptual representation of data structures and their interactions that will serve as a blueprint for how data will be stored, structured, and accessible in a database.

### Why is data modeling important?
Data modeling is an essential component of data management and system design. It entails developing a conceptual representation of data structures and their interactions that will serve as a blueprint for how data will be stored, structured, and accessible in a database. It helps to ensure that data is accurate, consistent, and accessible. Data models are also used to improve communication between business users and IT professionals.

In-depth advantages of data modeling include the following:

1. Data modeling assists in identifying and eliminating data discrepancies and redundancies. This results in higher data quality, which is necessary for making informed decisions.
2. Data models can be used to implement data security mechanisms such as access control and encryption, for example. This aids in the protection of sensitive data from unauthorized access.
3. Data models can be used to build databases and other data storage systems in such a way that data is easy to access and retrieve. This can boost business users' efficiency and productivity.
4. Better communication: Data models provide a standard language for data communication between business users and IT specialists. This can promote collaboration and lessen the likelihood of misunderstandings.
5. Reduced development costs: Data modeling can aid in the reduction of development and maintenance expenses for software systems. This is because data models can be used to construct a blueprint for the database that the application will use.

Data modeling is critical for a wide range of organizations, including enterprises, government agencies, and non-profits. It is especially critical for organizations that make decisions based on data, such as financial institutions, healthcare organizations, and retail firms.

Here are some concrete instances of how data modeling can be utilized to improve organizational performance:

1. A bank can utilize data modeling to create a database that keeps track of customer accounts, transactions, and investments. This information can be utilized to make more informed financing, fraud prevention, and marketing decisions.
2. A healthcare institution can utilize data modeling to create a database that keeps track of patient records, medical procedures, and insurance information. This information can be utilized to improve patient care, cut expenses, and meet regulatory requirements.
3. A retail organization can utilize data modeling to create a database that tracks consumer purchases, inventory levels, and sales patterns. This information can help enhance product selection, pricing, and marketing strategies.



### Types of data models.

There are several types of data models, each with a specific purpose:

### Conceptual Data Models.
These are high-level models that help in understanding business requirements and concepts. They provide a big-picture view of what the system will contain, how it will be organized, and which business rules are involved.
A Conceptual Data Model (**CDM**) is a high-level representation of data that is used to identify elements and their relationships. It is a high-level statement of the informational requirements that underpin the design of a database. It usually simply includes the core concepts and their main relationships. This model lacks technical details such as attributes, data types, and so on. 
The goal of a CDM is to define, describe, organize, and show data pieces and their relationships in as few details as possible. It is used to communicate with various business personnel when designing the database's business needs and providing concepts for their comments.
A Conceptual Data Model is a model that identifies the business concepts (entities) and the interactions between these concepts in order to learn, reflect, and document an understanding of the organization's business from a data viewpoint.

![conceptual data model](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ub24hbo04f48zw0ccd0w.png)

### Logical Data Models.
 
These models provide greater detail about the concepts and relationships in the domain under consideration. They define entity types, data attributes, and relationships between entities.

A Logical Data Model (**LDM**) is a data model that gives a precise, structured description of data pieces and their relationships. It encompasses all entities — a specific object transferred from the actual world (important to business) — as well as their relationships. These entities have defined their characteristics as their attributes.
The LDM is distinct from the physical database, which specifies how the data will be implemented. It acts as a blueprint for previously utilized data. The logical data model expands on the elements of conceptual data modeling by including more information. The logical data model combines all of the information pieces that are critical to the day-to-day operation of the business.

**Logical Data Model Components**
A Logical Data Model has the following components:

- **Entities**: Each entity is a collection of items, people, or thoughts that are relevant to a business.
- **Relationships**: Each relationship represents a connection between two of the entities listed above.
- **Attributes**: are descriptive pieces, characteristics, or any other information that can be used to further characterize an item. 

Each of these logical data model components is given a name and a written definition. These are used to continuously document company standards and specify information needs.
The LDM can explain the data requirements for each project. However, it is designed to interface effortlessly with other logical data models if the project requires it.
A logical data model can be created and constructed independently of a physical data model.A logical data model can be created and built independently of the database management system. It is unaffected by the type of database management system.
A logical data model is, in essence, a graphical depiction of the information needs of a business area.

 
![logical data model](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/j5keo73l2bopd4o45y96.png)

### Physical Data Models.
 These are specific implementations of the logical data model created by database administrators and developers. They represent the internal schema database design
A Physical Data Model (**PDM**) is a representation of a data design as it is or will be implemented in a database management system. It essentially describes the database's relational data structures and objects. It is written in the database management system's (DBMS) native database language. It can also be generated by modifying the logical model.
The PDM contains all of the logical database components and services needed to build a database or to layout an existing database. It includes the structure of the table, column names and values, foreign and main keys, and the relationships between the tables.
The PDM is a framework or architecture that explains how data is actually stored in a database. This physical data model is used to construct the actual schema of a database. This includes all of the tables, their columns, and the links between them.
Database managers use physical data models to assess the size of database systems and to plan capacity. The size, configuration, and security requirements of the physical data model can vary depending on the underlying database system.
To summarize, a Physical Data Model is a thorough depiction of how data is stored in the hardware of a computer. It depicts how data will be stored in and retrieved from physical storage devices such as hard drives and servers


![physical data model](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/vuejzmodqvxwwrpkmbls.png)

### Relational Data Models.
A relational data model is a method for developing relational databases that uses structure and linguistic consistency to manage data logically. Data in this model is represented as two-dimensional tables. Each table, which is made up of columns and rows, illustrates a relationship of data values based on real-world objects. These models organize data into tables that have connections among them.



![relational model](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ynhindt121tqr8e0gyal.png)



### Dimensional Data Models.
 These models are commonly used in data warehousing systems. They simplify complex databases by breaking down data into measurable chunks (facts) and descriptive categories (dimensions).
Dimensional data modeling is an analytical technique used in databases and data warehouses to organize and categorize facts into dimension tables. By creating a structure that isolates unrelated or insignificant data from the main body, this style of modeling facilitates quick retrieval of information from enormous datasets. The dimensional model also aids in the identification of links between different forms of data, allowing for a more in-depth examination of trends and patterns.
Ralph Kimball created it, and it comprises of "**fact**" and "**dimension**" tables.
Some key concepts in Dimensional Data Modeling are as follows:
- **Facts**: are the quantifiable data items that constitute the business metrics of interest. In a sales data warehouse, for example, the facts could comprise sales revenue, units sold, and profit margins.
- **Dimensions**: These are descriptive data pieces used to categorize or classify facts. Dimensions in a sales data warehouse, for example, could comprise product, customer, time, and location.
- **Characteristics**: Attributes are dimension characteristics in data modeling. These are used to filter, search for facts, and so on. Attributes for a location dimension can be State, Country, Zipcode, and so on.
- **Fact Table**: The fact table is the primary table of a dimensional data model that holds the measures or metrics of interest, surrounded by dimension tables that describe the properties of the measurements.
- **Dimension Table**: The dimension table lists the dimensions of a fact and connects them using a foreign key. Dimension tables are just tables that have been de-normalized.

The benefit of employing this approach is that we can store data in a fashion that makes it easier to store and retrieve data once it has been saved in a data warehouse. Many OLAP systems use the dimensional model as well.
Identifying the business objective, determining granularity (the lowest level of information recorded in the table), and creating Dimensional Data Modeling are all steps in the process.
The steps to create Dimensional Data Modeling involve determining the business aim, identifying granularity, and identifying dimensions and associated properties. 
This style of modeling allows for the rapid retrieval of information from big datasets by providing a framework that separates irrelevant or insignificant data from the main body. The dimensional model also aids in the identification of links between different forms of data, allowing for a more in-depth examination of trends and patterns


![dimensional modeling](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/rou1yjo8kssfvovhovup.png)

Other type of data models are:

### Entity-Relationship (E-R) Models.
 These models use a collection of basic objects, called entities, and relationships among these objects to represent data.
 
### Hierarchical Data Models.
 These models organize data in a tree-like structure with a single root to which all other data is linked. Each child record has only one parent.
### Network Data Models.
 These models allow each record to have multiple parent and child records, forming a web-like structure.
### Object-Oriented Data Models.
 These models organize data around objects rather than actions and data rather than logic.
### Multi-Value Data Models.
 These models are a type of NoSQL and multidimensional database that understands 3-dimensional data directly. They’re designed to handle large amounts of data, offering high performance and flexibility.

## Data Modeling Process.

1. **Requirements gathering.**
The first step is to gather requirements from stakeholders to understand how the data will be used. This includes identifying the different types of data that need to be stored, the relationships between the different data types, and the rules that govern the data.The process of gathering requirements for data modeling involves several steps:
  1. Identify the End-Users: The first step is to identify who will be using the data model. Understanding the capabilities and preferences of the end-user is crucial for designing an appropriate solution
  2. Help End-Users Define the Requirements: Assume that the end-users may not know everything they want or even that they will clearly define it to you. Talk with the end-user about their objectives and their difficulties. Help them define requirements by asking questions about business impact, semantic understanding, data source, frequency of data pipeline, and historical data.
   3. End-User Validation: Validate the requirements with the end-users to ensure that they accurately represent what the end-users need.
   4. Deliver Iteratively: Break down the project into small deliverables and deliver iteratively. This allows for feedback and adjustments as necessary.
   5. Handling Changing Requirements/New Features: Be prepared to handle changes in requirements or new feature requests. This is a normal part of any project and should be planned for.

2. **Conceptual modeling.**
Once the requirements have been gathered, the next step is to create a conceptual model of the data. The conceptual model is a high-level representation of the data that focuses on the business concepts and the relationships between them. It is not concerned with the specific implementation details of the database.Here’s a detailed explanation of the conceptual data modeling process:
   1. Identify Entities: The first step is to identify the basic objects or entities that are important for the business to represent in the data model. These are the tables of your database, such as students, courses, books, campus, employees, payment, projects.
   2. Define Relationships: Define the relationships between these entities. Relationships are the associations between the entities.
   3. Gather Business Requirements: Collect information about business requirements from stakeholders and end users. These business rules are then translated into data structures to formulate a concrete database design.
    4. Create Entity Relationship Diagram (ERD): An ERD is a pictorial representation of the information that can be captured by a database. It allows database professionals to describe an overall design concisely yet accurately. An ER Diagram can be easily transformed into the relational schema.
Validate Model with Stakeholders: Once you’ve created your conceptual model, validate it with your stakeholders to ensure it accurately represents their needs and expectations.
3. **Logical modeling.**
 The logical model is a more detailed representation of the data that focuses on the structure of the database. It identifies the specific database tables, columns, and data types that will be used to store the data. The logical model also defines the relationships between the different tables.
Here’s a detailed steps of a logical data modeling process:
   1. Identify Entities and Attributes: Based on the conceptual model, identify the entities and their attributes. These will be the tables and columns in your database.
   2. Define Relationships: Define the relationships between these entities. Relationships are the associations between the entities.
   3. Normalize Data: This step involves organizing data to minimize redundancy and dependency. It involves dividing a database into two or more tables and defining relationships between the tables.
   4. Create Logical Data Model Diagram: Create a diagram that represents entities, attributes, and relationships. This is typically done using an Entity-Relationship Diagram (ERD).
   5. Validate Model with Stakeholders: Once you’ve created your logical model, validate it with your stakeholders to ensure it accurately represents their needs and expectations.

4. **Physical modeling.**
The physical model is the most detailed representation of the data and focuses on the specific implementation details of the database. It specifies the physical storage characteristics of the database, such as the data types, indexes, and constraints
Here’s a detailed explanation of the physical data modeling process:
   1. Model Entities and Attributes: Define a table for each entity that is in the logical data model. Assign a name to each table. Create columns for each of the attributes of the entities.
   2. Define Data Types: For each attribute, define the data type, length, and any constraints such as NOT NULL or UNIQUE.
   3. Define Keys: Identify primary keys and foreign keys. Primary keys uniquely identify a record in a table, while foreign keys are used to link two tables together.
   4. Normalize Data: Organize data to minimize redundancy and dependency. This involves dividing a database into two or more tables and defining relationships between the tables.
   5. Create Physical Data Model Diagram: Create a diagram that represents entities, attributes, and relationships. This is typically done using an Entity-Relationship Diagram (ERD).
   6. Build DDL for Physical Data Model: Create the target database. This involves writing SQL statements to create tables, define relationships between them, and set up indexes.
   7. Design and Tune Performance: Design the physical model for optimal performance. This could involve creating indexes, partitioning large tables, or designing storage structures.
   8. Verify Physical Design: Make sure that you have addressed all business requirements and constraints.

5. **IMPLEMENTATION.**
The final step in the data modeling process is to implement the database. This involves creating the database tables, columns, and relationships based on the physical model.


## Conclusion.
We have discussed the key elements, categories, and procedures involved in developing a successful data model in this thorough examination of data modeling. A key factor in determining how businesses handle, store, and access their data is data modeling. Ensuring data integrity, consistency, and accessibility is a crucial procedure that eventually aids in making well-informed decisions.
Data modeling improves data quality by assisting organizations in locating and removing redundancies and inconsistencies in their data. Additionally, it makes it possible to put strong data security measures in place, guaranteeing that private information is kept safe. Furthermore, data models increase data accessibility, which increases user productivity and efficiency. They also act as a common language for business and IT experts to communicate with one another, which promotes cooperation and lowers miscommunication. Additionally, data modeling can lower maintenance and development expenses.
We explored the many kinds of data models in this post, each with a specific function in the field of data management. Conceptual data models offer a high-level comprehension of concepts and business requirements. More in-depth understanding of the links and structure of the data is provided by logical data models. Physical data models, on the other hand, concentrate on the particulars of the database's implementation. Alternative models that address distinct requirements and situations include relational, dimensional, and NoSQL.
Gathering requirements, conceptual modeling, logical modeling, and physical modeling are all steps in the data modeling process. With every step, the model gets more and more explicit, moving from a high-level conceptual representation to a thorough execution plan. Important components of this process include validation, iterative development, and stakeholder interaction.
To sum up, data modeling is a fundamental component of efficient data management, giving businesses the means to efficiently arrange and utilize their data. It guarantees that data is a useful tool for advancing corporate success rather than just an unprocessed collection of information. Since data is becoming more and more important in our digital era, data modeling will continue to be an essential technique for businesses looking to use their data to their advantage and make future-focused decisions.