Nowadays data is one of the most important things in the business world, every business captures its customers’ data to understand their behavior, in the world of the internet, data is growing like crazy, so businesses need more advanced database solutions, by which they can maintain the database systems and whenever they need data to solve business problems, they can easily get what data they want without any problem. To fulfill this condition, there is a requirement for the database schema in the picture.
Details of a Customer
Schema of Customer
There are 3 types of database schema:
Three Layer Schema Design
For creating a schema, the statement “CREATE SCHEMA” is used in every database. But different databases have different meanings for this. Below we’ll be looking at some statements for creating a database schema in different database systems:
1. MySQL: In MySQL, we use the “CREATE SCHEMA” statement for creating the database, because, in MySQL CREATE SCHEMA and CREATE DATABASE, both statements are similar.
2. SQL Server: In SQL Server, we use the “CREATE SCHEMA” statement for creating a new schema.
3. Oracle Database: In Oracle Database, we use “CREATE USER” for creating a new schema, because in the Oracle database, a schema is already created with each database user. The statement “CREATE SCHEMA” does not create a schema, instead, it populates the schema with tables & views and also allows one to access those objects without needing multiple SQL statements for multiple transactions.
There are many ways to structure a database, and we should use the best-suited schema design for creating our database because ineffective schema designs are difficult to manage & consume extra memory and resources.
Schema design mostly depends on the application’s requirements. Here we have some effective schema designs to create our applications, let’s take a look at the schema designs:
A flat model schema is a 2-D array in which every column contains the same type of data/information and the elements with rows are related to each other. It is just like a table or a spreadsheet. This schema is better for small applications that do not contain complex data.
Designing Flat Model
Data is arranged using parent-child relationships and a tree-like structure in the Hierarchical Database Model. Because each record consists of several children and one parent, it can be used to illustrate one-to-many relationships in diagrams such as organizational charts. Although obvious, it might not be as adaptable in complicated partnerships.
Designing Hierarchical Model
The network model and the hierarchical model are quite similar with an important difference that is related to data relationships. The network model allows many-to-many relationships whereas hierarchical models allow one-to-many relationships.
Designing Network Model
The relational model is mainly used for relational databases, where the data is stored as relations of the table. This relational model schema is better for object-oriented programming.
Designing Relational Model
Star schema is better for storing and analyzing large amounts of data. It has a fact table at its center & multiple dimension tables connected to it just like a star, where the fact table contains the numerical data that run business processes and the dimension table contains data related to dimensions such as product, time, people, etc. or we can say, this table contains the description of the fact table. The star schema allows us to structure the data of RDBMS .
Designing Star Schema
Just like star schema, the snowflake schema also has a fact table at its center and multiple dimension tables connected to it, but the main difference in both models is that in snowflake schema – dimension tables are further normalized into multiple related tables. The snowflake schema is used for analyzing large amounts of data.
Designing Snowflake Schema
Physical Schema
Logical Schema
Logical schema provides the conceptual view that defines the relationship between the data entities.
The design of database is independent to any database management system.
The design of a database must work with a specific database management system or hardware platform.
The database schema is defined before the actual database is created, after the database is operational, it is very difficult to modify the schema because the schema represents the fundamental structure of the database. Database instance does not hold any information related to the saved data in database. Therefore database instance represents the data and information that is currently stored in the database at a specific point in time.
Database instance of Customer table at a specific time
