Structure of Database Management System

Data modeling in the database is the modeling of the data. The data model defines the structure of the database (DBMS). This provides the conceptual tools for describing the design of the database. The structure of a database management system and the database architecture are two entirely different concepts. We have explained each idea in detail in the below sections.

However, before going through this concept, one must know the significant difference between these two.

Structure of the Database Management System

This is the combination of a database and its functionalities. This DBMS will allow the organization, access, and processing of data. This software will also allow us to interact with the data per our needs and views to get the data in the way we want.

The structure of the database management system is majorly divided into three categories. Below are the major types:

1. Conceptual Data Model

The conceptual data model describes a very high-level database model that will be useful to understanding. This model will be implemented in the requirement-gathering phase, where the database designers will start creating the database. One of the popular data models of this type is ER (Entity Relationship).

2. Representation Model

The representation model represents only the logical part of the database. It primarily focuses on the database’s design and can be used as a theoretical concept to implement the database design.

3. Physical Data Model

This is used to implement the relationship data model, which describes how the system will implement the database model. It defines the different forms of physical storage of data, such as disks, files, and other data structures.

Database Management System

Database Management System (DBMS) is a software technology program that allows us to create the database, delete the data, and select the data. This can be done using authorized entities.

Various roles can be assigned to perform the different kinds of operations.

Example: Admin can perform select, update, delete, and grant permission to the users.

Users: Using the DBMS, we can give different kinds of permissions, such as read-only, read-and-write, and customized access.

1. Storing the Data: We can store the data by creating tables and inserting the values into it.
2. Manipulating the Data: Manipulating data is to retrieve, fetch, and get the data as per the user's need.
3. Update/Delete the Data: It updates/deletes the data stored in the database.
4. Protecting the Data: It protects the data from any attack and ensures it is more secure.

Thus, to summarize, by implementing the methods of structure of a database management system, developers will be relieved of maintaining the data physically. Also, they can get a consolidated view of the data anytime.

Data Modelling

Data modeling includes modeling of data description, semantics, and consistency constraints. It can be used as a conceptual tool to design the database at each level.

There are four types of data models in DBMS. Below are the types.

1. Relational: This represents the data model in row and column based. Hence, this uses a table to represent the data.
2. Semi-structured: We can represent the data model of this type in the form of XML (Extensible Markup Language). This model allows the data to be specified in a few places where the data items are of the same type but have different attributes.
3. Entity Relationship: This represents the data model logically representing data and its relationships as objects. These objects are known as entities, and their relationship is called an association.
4. Object-Based: This is an extension of the ER model. In addition, we can represent the data model in the form of notions, functions, etc.

Advantages of Using the Data Model

1. It helps to represent data accurately.
2. It minimizes data redundancy and also helps to find the missing data.
3. It provides the data security.
4. Using the data model, we can define the relationship between the data.
   

Architecture Diagram

Three primary roles of the database management system's structure.

1. DBA: This has the schema, compiler, and optimizer. Each performs its respective operation.
2. Users: To run the queries and handle the transactions.
3. Application Programs: Compile the application programs using the DML compiler.
   

Objective of Architecture Diagram

1. We can give different views of data for the different types of users.
2. Users need not worry about the physical implementation and its process.
3. All users should be able to access the data they want.

The architecture of a database system: There are three types of tiers in the architecture diagram.

One-Tier Model

In a one-tier architecture model, the user can access the database directly. All the clients, servers, and databases are available on a single machine. Any changes made by the user will be directly made to the database itself. This type of architecture can be used for a local application.

Two-Tier Model

The two-tier architecture model is like a client-server model. The application is on the client side, and the database is on the server side. For this interaction between the client and the server, we can use APIs like ODBC, JDBC, etc. This user interface and the application will run on the client side.

Using a database connector, we can establish the connection between the client and server.

Three-Tier Model

In a three-tier model, there is a layer between the client and server. Hence, the client cannot directly communicate with the server. The client application interacts with the server, which in turn connects with the database.

Each type of architecture model should be implemented based on the requirements and its usage.

Components of DBMS

There are three components in the DBMD. We are going to see each in detail in the below section.

1. Query Processor
2. Storage Manager
3. Disk Storage
   

Query Processor

The query processor transforms the user's query into a result-based one. It processes the query straightforwardly and easily. This processor handles all queries only. It will execute the user request from the DML compiler.

Components of Query Processor

• DDL Interpreter: This data definition language interprets the DDL by creating and removing schema. Using this interpretation, we can keep the metadata in the data dictionary.
• DML Compiler: This is a data manipulation language that manipulates the data like select, update, delete, etc. Using this function, we can also optimize the query.
• Embedded DML Pre-compiler: This embeds the DML commands, such as SELECT and FROM, into the application program for execution before the query evaluation. This will be pre-compiled before the execution.
• Query Optimizer: It evaluates and analyses the query statements before returning the result. It is in charge of analyzing the query and running the object code. Some examples of query optimizers are Apache Drill and Presto.
  

Storage Manager

The database stores the data, and users will access them using the queries. Storage manager acts as an interface between these two. This, in turn, helps to manage the integrity and consistency of the data. This is also called a database control system. It is also responsible for retrieving, storing, and removing data from the database.

Components of Storage Manager

• Integrity Manager: Check the integrity of the database whenever the database is modified.
• Authorization Manager: This ensures role-based access control to check the privileges and whether the given person has the right to perform a particular action.
• File Manager: The structure of the files and their spaces is maintained here.
• Transaction Manager: It maintains the concurrency before and after the transaction is performed.
• Buffer Manager: Managing the memory of the data during the data transfer and cache memory is handled here.

Disk Storage

Storing the data in different forms in the form of a disk.

Components of Disk Storage

• Data Dictionary: Give metadata or information about the structure of the database. It is the repository of information that governs the metadata.
• Data Files: Stores the data.
• Indices: Provides faster access and retrieval of data.
  

Final Words

Data modeling is used as the process to develop the data model to be stored in the databases. It ensures the consistency and security of the data. The structure of the DBMS is implemented using the three major types of the database model. However, the biggest challenge when implementing the database management system is, that even for a small change, it should take modifying the entire application at many places.

FAQs

1: What are the four types of database models?
A: The four types of database models are entity relationship, object-oriented, semi-structured, and relational models.

• Entity Relationship Model: Logical way of representing data using the ER Diagram.
• Object-Based Model: The object-based data model is the extension of the ER model. This helps to represent using notions, and functions.
• Semi-structured: XML-based. It helps to get metadata information about the data.
• Relational Model: Represented using relations and entities.

2: What is a data model diagram?
A: The data model diagram represents data modeling by implementing the database design.

3: What is a data model in DBMS?
A: The data model is a modeling of data. This allows the developers to model the data description, consistency, and constraints.

4: What is a conceptual data model in DBMS?
A: This is a high-level database model. It represents the model in the form of an Entity relationship or in a logical way of designing the database.

5: What are the three main database models?
A: The three major database models are conceptual, relational, and physical.

• Conceptual Model: Represented using high-level models like ER.
• Relational: Represented using the theoretical concept.
• Physical: Represents some form of storage like disk, storage, files, and records.