A database is an organized collection of data, generally stored and accessed electronically from a computer system. Where databases are more complex they are often developed using formal design and modeling techniques. The database management system (DBMS) is the software that interacts with end users, applications, and define, manipulate, retrieve and manage data in a database.
The DBMS software additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a "database system". Often the term "database" is also used to loosely refer to any of the DBMS, the database system or an application associated with the database. A DBMS generally manipulates the data itself, the data format, field names, record structure and file structure. It also defines rules to validate and manipulate this data. Thus, it relieves users of framing programs for data maintenance. Fourth-generation query languages, such as SQL, are used along with the DBMS package to interact with a database.
Relational Database: Data is organized as logically independent tables. Relationships among tables are shown through shared data. The data in one table may reference similar data in other tables, which maintains the integrity of the links among them. This feature is referred to as referential integrity – an important concept in a relational database system. Operations such as "select" and "join" can be performed on these tables. This is the most widely used system of database organization Here, is the list of some popular DBMS system:
- MySQL
- Microsoft Access
- Oracle
- MongoDB
- PostgreSQL
You can learn any one of the above from the resourses given below.
MySQL is currently the most popular database management system software used for managing the relational database. It is open-source database software, which is supported by Oracle Company. It is fast, scalable, and easy to use database management system in comparison with Microsoft SQL Server and Oracle Database. It is commonly used in conjunction with PHP scripts for creating powerful and dynamic server-side or web-based enterprise applications.
MySQL is open source and can be downloaded from here. Detailed steps for how to install MySQL.
- Introduction
- Commands for Queries
- Tutorial
- Exercise
- Practice Problems
- Some Useful Links
Oracle Database (commonly referred to as Oracle RDBMS or simply as Oracle) is a multi-model database management system produced and marketed by Oracle Corporation. It is a database commonly used for running online transaction processing (OLTP), data warehousing (DW) and mixed (OLTP & DW) database workloads. The latest generation, Oracle Database 19c, is available on-prem, on-cloud, or in a hybrid-Cloud environment. 19c may also be deployed on Oracle Engineered Systems (e.g. Exadata) on-prem, on Oracle (public) cloud or (private) cloud at customer.
Oracle can be freely downloaded from its official website. Steps to install Oracle Database.
- Introduction
- Tutorial 1
- Tutorial 2
- Exercise
- Useful Links
MongoDB is a cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schema. MongoDB is developed by MongoDB Inc. and licensed under the Server Side Public License (SSPL). MongoDB supports field, range query, and regular-expression searches. Queries can return specific fields of documents and also include user-defined JavaScript functions. Queries can also be configured to return a random sample of results of a given size.
MongoDB can be downloaded from its official website. Installation Manual for installing MongoDB.
- Introduction
- Tutorial
- Useful Links
PostgreSQL also known as Postgres, is a free and open-source RDBMS emphasizing extensibility and SQL compliance. It was originally named POSTGRES, referring to its origins as a successor to the Ingres database developed at the University of California, Berkeley. In 1996, the project was renamed to PostgreSQL to reflect its support for SQL. After a review in 2007, the development team decided to keep the name PostgreSQL.
PostgreSQL is open source and can be downloaded from website. Steps to install PostgreSQL.
- Introduction
- Tutorial 1
- Tutorial 2
- Useful Links