The Journey of Database !!

The concept of a database existed long before computers. In these times, data was stored in journals in libraries. Everything was recorded via paper which makes it difficult to store/update/read/backup data. And then computers became available, and with them, the opportunity for better data management.

Data modelling and databases evolved together, and their history dates back to the 1960’s.

In early 1960's IMS was developed and it is a hierarchical database model. It is honoured as the first ever Database system developed in the IT world. The incredible thing about IMS is that it is still used by many of the large scale industries such as banks, healthcare etc . One good reason is its capability to handle huge volume of information without compromising the speed of transactions. Just imagine the number of Transactions a bank handles every minute !!

A few years later, another type of database was developed in 1970's which is called IDMS. This is a Network model. IDMS is also practically very fast and can also hold a large volume of information. Unlike IMS, It can allow for more complex and overlapping hierarchies. There are many companies which still use IDMS.

Databases such are IMS and IDMS are named as 'dinosaur' because they are so old. But an interesting question could be , 'If it is too old, why 95% of the Fortune 1000 companies are still using them?'  Well, the reason could be the Along with handling large volume of data and faster retrieval, these technologies are flexible enough to support modern technologies, including cloud and mobile.

Ok, Let's continue our discussion to the next phase of invention which is RDBMS after 1980’s. Some good examples could be DB2 or Oracle. Because it follows ACID Rule, it became very convenient to use. On top of it, SQL made programmer's life so easy. The database administration also became lot more easier. So RDBMS and SQL became the new favourite of newly built industries. 

However, the new era of IT world talks about NoSQL (Not-only SQL) databases which are not relational anymore. In late 2000's when the cost of storage dramatically decreased, there was no need to create complex models to store data. Developers (rather than storage) were becoming the primary cost of software development, so NoSQL databases optimized for developer productivity. It is important to know that No-SQL supports ACID rule and it can hold relational data. 

I used one set of entity-relationship and tried to create the possible datamodel in all Databases that I am familiar with.

Data model Entities are : Department - Employee - Skill