A database is a collection of data that is stored in an organized manner. This data can either be on a computer or on paper. It is, of course, more efficient to store data on a computer like you can learn in this course, as the computerization of this data makes it easy to retrieve and perform operations on. Today, in the information age, databases of some kind are maintained by all organization, big and small. They are essential in ensuring that the day to day operations of an organization can run smoothly.
An Introduction to Database Systems
There are several software-based products that help you build and maintain databases. These software products are known as database management systems (DBMS). In addition to letting you build a database, most DBMS applications will interact with a user, or multiple users. They will also let you perform operations on the data in their repository. DBMS systems are always based on a computer language (which can vary). A user has to type commands in this language if he wants to interact with the data on the system – as well as the software he is using.
Key Difference between DBMS and RDBMS
So what is the main difference between DBMS and RDBMS? The key difference is that RDBMS (relational database management system) applications store data in a tabular form, while DBMS applications store data as files. Does that mean there are no tables in a DBMS? There can be, but there will be no “relation” between the tables, like in a RDBMS. In DBMS, data is generally stored in either a hierarchical form or a navigational form. This means that a single data unit will have one parent node and zero, one or more children nodes. It may even be stored in a graph form, which can be seen in the network model.
In a RDBMS, the tables will have an identifier called primary key. Data values will be stored in the form of tables. The relationships between these data values will be stored in the form of a table as well. Every value stored in the relational database is accessible. This value can be updated by the system. The data in this system is also physically and logically independent.
You can say that a RDBMS is an in an extension of a DBMS, even if there are many differences between the two. Most software products in the market today are both DBMS and RDBMS compliant. Essentially, they can maintain databases in a (relational) tabular form as well as a file form, or both. This means that today a RDBMS application is a DBMS application, and vice versa. However, there are still major differences between a relational database system for storing data and a plain database system.
History of DBMS and RDBMS
Database management systems first appeared on the scene in 1960 as computers began to grow in power and speed. In the middle of 1960, there were several commercial applications in the market that were capable of producing “navigational” databases. These navigational databases maintained records that could only be processed sequentially, which required a lot of computer resources and time.
Relational database management systems were first suggested by Edgar Codd in the 1970s. Because navigational databases could not be “searched”, Edgar Codd suggested another model that could be followed to construct a database. This was the relational model that allowed users to “search” it for data. It included the integration of the navigational model, along with a tabular and hierarchical model.
The Client Server Architecture
Database management systems like the ones you’ll learn about in this course (at least the pure DBMS applications) do not support the client-server architecture, while relational database management systems do. What is the client-server database model exactly? In a client-server database model, data is stored in a central location on a server. This server can share the data between one or more users, which are referred to as clients. However, this is not a distinction that is relevant today, where a DBMS program is a RDBMS program, and vice versa.
Ease of Access
It is generally easier to access data that is stored in a relational database. This is because the data in a relational database follows a mathematical model for categorization. Also, once we open a relational database, each and every element of that database becomes accessible, which is not always the case with a normal database (the data elements may need to be accessed individually).
It is also easier to find data in a relational database. You can “query” a relational database in its native language without knowing the value of a key or index.
Relational databases are harder to construct, but they are better structured and more secure. They follow the ACID (atomicity, consistency, isolation and durability) model when storing data. The relational database system will also impose certain regulations and conditions that may not allow you to manipulate data in a way that destabilizes the integrity of the system.
In a regular database, the data may not be stored following the ACID model. This may introduce inconsistencies in the database. It may even cause the database to become unstable over time or it may put the security of the data at risk.
The Best Database Management Program in the Market
At the moment, if you look at sales, Oracle is the best database management system in the market. There’s a great beginners course for Oracle here. It is far ahead of its nearest competitors, which include IBM (DB2 UDB), SAP, Microsoft (SQL Server) and Teradata. Oracle is produced and marketed by the Oracle Corporation. Oracle and IBM have a working partnership of sorts- many of their products are compatible with each other (mostly because they share the same customers).
The Oracle database can be queried through PL/SQL (Procedural Language/ Structured Query Language). PL/SQL is derived from the Pascal language, and its coding bears a striking similarity to Ada. If you are familiar with Java or C++, you will find it easy to learn PL/SQL.
If you’re looking to become a system administrator, you can either get yourself a copy of Oracle or you can look at some of the open source alternatives in the market today like Firebird, MySQL and PostgreSQL. Here at Udemy, we have lots of courses to help you learn whatever system administration tool interests you, like this beginner’s course on MySQL development.