RDBMS stands for Relational Database Management System. It is a type of database management system that is based on the relational model, which organizes data into tables with rows and columns, and uses relationships between tables to link data together.
In an RDBMS, data is stored in tables, with each table representing a specific type of data (such as customers, orders, or products). Each table has columns that represent the attributes of the data, and rows that represent individual instances of the data. Relationships between tables can be established using keys, allowing data from multiple tables to be linked and retrieved in a single query.
RDBMSs provide a variety of features and tools for managing, querying, and manipulating data stored in the database, including data validation, constraint enforcement, transaction management, backup and recovery, reporting and analysis capabilities. They are widely used in enterprise applications, web applications, and other systems that require the management of large amounts of structured data.
Examples of popular RDBMSs include Oracle, Microsoft SQL Server, MySQL, and PostgreSQL.
A Relational Database Management System (RDBMS) uses Data Manipulation Language (DML) and Data Definition Language (DDL) queries to interact with the data stored in the database. The specific syntax of the queries will vary depending on the database system being used.
DML queries are used to retrieve, insert, update, and delete data in the database. The most used DML queries are:
- SELECT: Retrieves data from one or more tables in the database.
- INSERT: Adds a new row of data to a table in the database.
- UPDATE: Modifies existing data in a table in the database.
- DELETE: Deletes data from a table in the database.
DDL queries are used to create, modify, and delete database structures, such as tables, indexes, and constraints. The most used DDL queries are:
- CREATE: Creates a new database object, such as a table or index.
- ALTER: Modifies the structure of an existing database object.
- DROP: Deletes a database object.
For example, the following is a DDL query to create a table named customers:
CREATE TABLE customers ( id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(255), email VARCHAR(255), address VARCHAR(255) );
And the following is a DML query to insert a new customer into the customers table:
INSERT INTO customers (name, email, address)
VALUES ('John Doe', 'johndoe@example.com', '123 Main St');
In the next article we will be talking about the origin of data access in net framework a.k.a ADO.NET
See you then )))
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