Evolution of Data-base systems
The objective of this assignment was to research and formulate a report about the advancement in data-base systems technology over the years, my analysis is broken down not only in respective time-periods of development but it also entails the various advantages a certain system had over its predecessors and the subsequent generation that it was dubbed by the experts of the time.1960's Flat Files and the Genesis of DBS
The 60's was the era when computers found wide-spread use outside the lab and they were accepted by the general scientific community and as a useful and invaluable tool, at that time the dominant system in use for storing data and managing it was traditional File-processing or filing capabilities that were provided by standard programming languages, as we already know, these systems suffered from many types of disadvantages that are faced by utilizing such systems e.g. program data dependency, limited data sharing, data duplication etc, although it cannot be said that the first generation of DBS arrived in this era, but it is historically quite certain that DBS's were conceived at this time, namely:
* The need for Data-base systems was realized and in a few complex projects, e.g. In the landing of the Apollo craft on the moon, the Information Management System developed by IBM in 1968 was used.
* An effort was made towards the standardization of DBS resulting in the formation of "The Data Base Task Group" by Charles Bachman at CODASYL (Conference Of Data System Languages, This group was also responsible for the creation of COBOL).
Before proceeding, it should be mentioned here that CODASYL's software and IMS are characterized as Navigational Databases, they operate using pointers, the searching mechanism uses sequential searching algorithms, and this is partially the case due to the availability on only magnetic tape storage technology at the time.1970s Commercialization and the appearance of 1st Generation DBS
After the first major hurdles were removed and a way was paved for Data-Base systems, their commercial value was realized by different organizations and the ball was set to roll in this era which would later come to be known as the 1st Generation of DBS. Although hierarchal DBS (IBM's IMS) were available as soon as 1968, it took the industry almost four years to accept and start the implementation of these systems.
It should be understood here that both types of Navigational DBS were not flawless, especially the hierarchal DBS was based on a parent-child relationship similar to that of a Tree Data structure, although this provided the DBA (Data Base Administrator) some level of control over the data, it was still very tedious and time consuming to traverse records (as no relationship was established between children themselves), this resulted in three major discrepancies:* There is still a certain level of program data dependency, namely:
ÂÂ¨ Ordering Dependency
ÂÂ¨ Indexing Dependency
ÂÂ¨ Access Path Dependency
Although the problems mentioned above pertained and inhibited the steady working of organizations that had employed DBS these methods stayed dominant from the late 60s to the early 80s.1980s 2nd Generation, Relational DBMS
In the 80's it was widely felt by the industry that the then current DBS under usage were hindering performance in a lot of ways, many DBAs were having reservations about the continued enhanced productivity from these systems as the data to be operated upon kept on increasing in magnitude, E.F Codd started his work on Relational Database systems when he published a paper on the subject in 1970, he would go on to make refinements in the model as late as 1985 but his model which based solely upon mathematical principles such as set theory and first order predicate logic proved far superior to Navigational databases, he proposed twelve rules (famously known as Codd's Rule) which according to him should be in conformity with any RDBS but we will only discuss three major ones that have significance to our discussion, the major advantages of this model were:
* Following the guaranteed access rule, an RDBMS provides easy and quick access to all data as records are interlinked using keys since the relational model orders data in its natural structure.
* By following the physical and logical Data Independence rule, RDBMS ensures that application programs do not have to be modified and this results in true Program-Data Independence.
* The Integrity Independence rule ensures minimum data corruption.
* One of the major benefits of RDBMSs was that they could be used by a 4th generation programming language SQL (Simple Query Language), this made it a lot easier for non-programmers to work with databases.
These types of systems prevailed well into the mid 90's and they provided compatibility with quite new and innovative advancements made in Computer Science e.g. Client-Server Computing, Parallel Processing and Graphical User Interfaces. The most successful of these systems were the Oracle v6 & v7.1990s Object Oriented DBMS
As mentioned earlier, RDBMSs were quite efficient till the mid 90's, it was around this time that complex types of data came into play more often, such data (mostly multi-media, images, videos etc) was unstructured and it was beyond the capabilities of RDBMS to handle it so a new model was introduced which came to be known as the Object Oriented DBMS. The concept was first introduced in a paper by Malcolm Atkinson, FranÃÂ§ois Bancilhon, David DeWitt, Klaus Dittrich, David Maier and Stanley Zdonik in 1993, later on the task of standardizing OODBS was taken up by ODMG (Object Data Management Group), the widely accepted and most implemented standard is the ODMG 3.0 different advantages of OODBS over their predecessors are:
* OODBSs provide the unique capability to store complex data types as objects & provides full OO functionality.
* For the first time, DBSs were used as more than just filing cabinets; developers working with OO languages could use OODBSs to store their defined routines without relationally disassembling them.
* This resulted in reduced programming errors and software recycling trends.Extrapolation of Future Trends:
Although it has been seen that DBSs have evolved significantly in various ways, from the early magnetic tape storages to complex and efficient state-of-the-art storage units of today, from early Navigational models to advanced ORDBMS and Hyper-databases, the road to perfection is never ending, I'd like to conclude my argument with two major up-and-coming advancements in DBS:Object Relational DBS
As the name implies, these types of DBSs are a hybrid between OODBMSs and RDBMSs, they originated when RDBMS vendors started to address the deficiencies in their systems by providing object oriented properties and it has sparked quite a lot of interest in both business and research environments, mainly because users can easily upgrade their existing RDBMSs to ORDBMS easily, currently Oracle 8i & 9i are significant examples.Hyper-Databases
This significantly novel concept has recently been put forward in a paper published in the Database Engineering & Applications, 2001 International Symposium. The author is Hans-Jorg Schek from the
Swiss Federal Institute of Technology, Zurich, Switzerland Institute of Information Systems, Database Research Group. Below is the Abstract of his paper:
"Hyper-databases move up to a higher level, closer to the applications. A hyper-database manages distributed objects and software components as well as workflows, in analogy to a database system that manages data and Transactions. In short, hyper-databases will provide "higher order data independence", e.g., immunity of applications against changes in the implementation of components and workload transparency. Such an evolution of database technology should keep its pivotal role as infrastructure for application development for data-intensive, central and distributed application. The Hyper-database concept abstracts from the host of current infrastructures and middleware technology." [Schek, H.-J; 2001]References and Citations
Article name: Data-base systems essay, research paper, dissertation