Which of the following are some common RDBMS in use?

Some common Relational Database Management Systems (RDBMS) in use are:

1. Oracle Database: This is a highly scalable RDBMS architecture that is commonly used in global enterprises, which manage and process data across wide and local area networks.

2. MySQL: This is an open-source RDBMS that relies on SQL for processing the data in the database. MySQL provides APIs for the languages C, C++, Eiffel, Java, Perl, PHP and Python.

3. Microsoft SQL Server: This is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications.

4. PostgreSQL: This is an advanced, enterprise-class, and open-source relational database system. PostgreSQL supports both SQL (relational) and JSON (non-relational) querying.

5. SQLite: This is a software library that provides a relational database management system. The lite in SQLite means light weight in terms of setup, database administration, and required resource.

6. IBM DB2: This is a family of database server products developed by IBM. These products all support the relational model, but in recent years, some products have been extended to support object-relational features and non-relational structures like JSON and XML.

7. MariaDB: This is a community-developed, commercially supported fork of the MySQL relational database management system, intended to remain free and open-source software under the GNU General Public License.

Some common Relational Database Management Systems (RDBMS) in use are:

1. Oracle Database: It's a highly scalable RDBMS architecture that's commonly used in global enterprises, which manage and process data across wide and local area networks.

2. MySQL: It's an open-source RDBMS that relies on SQL for processing the data in the database. MySQL provides APIs for the languages C, C++, Eiffel, Java, Perl, PHP and Python.

3. Microsoft SQL Server: It's a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications.

4. PostgreSQL: It's a powerful, open source object-relational database system that uses and extends the SQL language combined with many features that safely store and scale the most complicated data workloads.

5. SQLite: It's a C library that provides a lightweight disk-based database that doesn’t require a separate server process and allows accessing the database using a nonstandard variant of the SQL query language.

6. IBM DB2: It's a family of database server products developed by IBM. These products all support the relational model, but in recent years, some products have been extended to support object-relational features and non-relational structures like JSON and XML.

To determine some common RDBMS in use, we can follow these steps:

1. Research: Start by conducting research to gather information about popular RDBMS (Relational Database Management Systems) currently in use.

2. List of RDBMS: Based on the research, create a list of commonly used RDBMS. Some examples may include:

• MySQL
• Oracle Database
• Microsoft SQL Server
• PostgreSQL
• IBM DB2
• SQLite

3. Evaluate popularity: Assess the popularity and usage of each RDBMS by considering factors such as market share, community support, and industry adoption.

4. Additional considerations: Take into account specific requirements or preferences, such as scalability, performance, cost, and compatibility with programming languages or frameworks.

5. Final selection: Based on the research, popularity, and specific requirements, choose the RDBMS that best fits the needs of the project or organization.

Remember that the choice of RDBMS may vary depending on the specific use case, so it's important to thoroughly evaluate the options before making a decision.