Relational databases

Entities: Entities describe objects, persons, or concepts that are relevant to the database. They are the building blocks of a relational database.

Attributes: Attributes are properties of entities, which are used to describe or identify them.

Relationships: Relationships define the connections between different entities. They describe how one or more entities are related to each other.

Keys: Keys are used to uniquely identify entities in a database. They can be primary keys or foreign keys.

Data types: Data types define the type of data that can be stored in a database. Some common data types include text, numbers, and dates.

Normalization: Normalization is the process of organizing data in a database to minimize redundancy and improve data integrity.

Constraints: Constraints are rules that are applied to the data in a database to ensure that it follows certain guidelines.

Indexes: Indexes are used to improve the performance of queries by creating a quick reference to the data that is being searched.

Stored procedures: Stored procedures are pre-written code that can be stored in a database and used to automate tasks.

Transactions: Transactions ensure the consistency and integrity of the data in a database by grouping a series of database operations together and treating them as a single unit.

Views: Views are virtual tables that can be used to simplify complex queries or simplify access to data.

Joins: Joins are used to combine data from multiple tables in a database into a single result set.

Query languages: Query languages are used to interact with the database and retrieve data. Examples include SQL.

Database design: Database design is the process of creating a database schema that is optimized for storing and retrieving data.

Data modeling: Data modeling is the process of creating a conceptual representation of data in a database, which includes defining entities, relationships, and attributes.

Oracle Database: Developed by the Oracle Corporation, Oracle database is a massively scalable and secure RDBMS that allows users to manage large datasets with ease. It is widely used by businesses and other organizations that require advanced data processing capabilities.

MySQL: MySQL is an open-source RDBMS that is used globally by businesses of all sizes. It is particularly popular with small and medium-sized enterprises because it is easy to use and cost-effective.

Microsoft SQL Server: Microsoft SQL Server is one of the most popular RDBMSs in use today. It is particularly well-suited for businesses that use Microsoft technologies, such as Windows operating systems and Microsoft Office products.

IBM DB2: IBM DB2 is a powerful RDBMS that is widely used in large corporate environments. It provides users with advanced data processing capabilities, high availability, and robust security features.

PostgreSQL: PostgreSQL is another open-source RDBMS that is popular with businesses of all sizes. It is particularly well-suited for businesses that require advanced data processing capabilities, such as those involved in scientific research or financial analysis.

SQLite: SQLite is a lightweight RDBMS that is particularly well-suited for use on mobile devices or other embedded systems. It is widely used in applications that require fast, reliable data storage and retrieval.

MariaDB: MariaDB is an open-source RDBMS that was developed by the original creators of MySQL. It is particularly popular with businesses that require a high degree of performance and reliability.

Sybase ASE: Sybase ASE is a fast and reliable RDBMS that is particularly well-suited for large-scale applications. It was developed by Sybase, a company that was later acquired by SAP.

Teradata: Teradata is an RDBMS that was developed specifically for data warehousing and analytics. It is widely used by businesses that require advanced data processing and analysis capabilities.

Informix: Informix is an RDBMS that was developed by IBM. It is particularly well-suited for large-scale enterprise applications that require robust performance, reliability, and security.