HISTORY OF DBMS

History of Database Systems:

 1950s and early 1960s:

•   Magnetic tapes were developed for data storage 
•  Data processing tasks such as payroll were automated, with data stored on tapes. 
•  Data could also be input from punched card decks, and output to printers. 
•  Late 1960s and 1970s: The use of hard disks in the late 1960s changed the scenario for data processing greatly, since hard disks allowed direct access to data. 
• With disks, network and hierarchical databases could be created that allowed data structures such as lists and trees to be stored on disk. Programmers could construct and manipulate these data structures. 
•  With disks, network and hierarchical databases could be created that allowed data structures such as lists and trees to be stored on disk. Programmers could construct and manipulate these data structures.
•   In the 1970’s the EF CODD defined the Relational Model. 

In the 1980’s:

•   Initial commercial relational database systems, such as IBM DB2, Oracle, Ingress, and DEC Rdb, played a major role in advancing techniques for efficient processing of declarative queries. 
•  In the early 1980s, relational databases had become competitive with network and hierarchical database systems even in the area of performance. 
•  The 1980s also saw much research on parallel and distributed databases, as well as initial work on object-oriented databases.

 Early 1990s:

•   The SQL language was designed primarily in the 1990’s. 
•  And this is used for the transaction processing applications. 
•  Decision support and querying re-emerged as a major application area for databases.
•  Database vendors also began to add object-relational support to their databases.

 Late 1990s:

•   The major event was the explosive growth of the World Wide Web
• .  Databases were deployed much more extensively than ever before. Database systems now had to support very high transaction processing rates, as well as very high reliability and 24 * 7 availability (availability 24 hours a day, 7 days a week, meaning no downtime for scheduled maintenance activities).
•   Database systems also had to support Web interfaces to data. The Evolution of Database systems:

 The Evolution of Database systems are as follows:

• 1.File Management System 
• 2.Hierarchical database System 
• 3.Network Database System 
• 4.Relational Database System 

1.File Management System:

 The file management system also called as FMS in short is one in which all data is stored on a single large file. The main disadvantage in this system is searching a record or data takes a long time. This lead to the introduction of the concept, of indexing in this system. Then also the FMS system had lot of drawbacks to name a few like updating or modifications to the data cannot be handled easily, sorting the records took long time and so on. All these drawbacks led to the introduction of the Hierarchical Database System.

2. Hierarchical Database System:

 The previous system FMS drawback of accessing records and sorting records which took a long time was removed in this by the introduction of parent-child relationship between records in database. The origin of the data is called the root from which several branches have data at different levels and the last level is called the leaf. The main drawback in this was if there is any modification or addition made to the structure then the whole structure needed alteration which made the task a tedious one. In order to avoid this next system took its origin which is called as the Network Database System.

Hierarchical structure

Network Database System:

 In this the main concept of many-many relationships got introduced. But this also followed the same technology of pointers to define relationships with a difference in this made in the introduction if grouping of data items as sets.

Network database model diagram

Relational Database System:

 In order to overcome all the drawbacks of the previous systems, the Relational Database System got introduced in which data get organized as tables and each record forms a row with many fields or attributes in it. Relationships between tables are also formed in this system.

Relational table