A Review On A First Database System Information Technology Essay
First database system was introduced in 1968 using flat files. Flat files were used to implement database in a single file. Flat files database system is also known as flat database system or flatform database. It is called flat database system because these databases cannot represent relationship between data. Flat files database consists of single big table instead of many interconnected tables with relationship between them. There is no specific format for writing a flat file, data is separated by comma. This database system has many disadvantages for example searching in this type of database system is much complicated and time consuming, and updating and sorting of data is not quite easy. For example if someone wants to retrieve the 1000th record, he/she first has to go through the first 999 records.
Hierarchical approach was then introduced in early 70s to create databases. In A hierarchical data model implements database using tree like structure. It makes a parent-child relationship between different records in database. The start of the data is called the root from which several branches originate which have records at different levels and the last level is known as leaf. They are based of binary trees such that each child can have one parent. It is better than flat database because of efficient searching and less redundant data but the main shortcoming of this type of database system is that if any modification is needed then the complete structure has to be changed accordingly. Moreover they have only some degree of data dependence and they are difficult to manage.
The network model's original inventor was Charles Bachman at Honeywell, Integrated Data Store (IDS). Network database model is just like hierarchical database model in fact it is more advanced form of hierarchical database model. The network data model overcomes some of the limitations of the hierarchical data model. It uses the same logic as that of hierarchical database model except it not implemented using binary tress and due to that it allows each child to have multiple parents which results in many to many relationship. This database holds addresses of other users in the network. In this each set has owner record and member record. The main setback is system complexity and hard to design and maintain.
To overcome the limitations of flat, hierarchical and network models, E. F. Codd Introduced the relational data model. It is a collection of data items organized as set tables from which data can be accessed or modified in many different ways without having to change the database tables which was its biggest advantage over other data models. SQL language is used in relational database system. This type of database is easy to create, access, modify and above all it is easy to extend. Due to all of these advantages relational data models took over all the previous types of data models and they are currently the predominant choice in storing data like financial records, medical records, personal information and manufacturing and logistical data. In this data get ordered in different tables and each record forms a row with different fields and attributes in it. Relationships between different tables are also formed in this system. In this database user interacts with only a logical view of the data and he is only interacts with the interface, and he do not know about the internal structure that is why it can be easily accessed by non programmers.
Object oriented database was introduced in 1985 and it is a database model in which the data is represented in form of objects. It is also known as Object Database Management Systems (ODBMS). Objects are used in languages like C++, java etc. An object has its attributes which define its characteristics and its methods which are also called functions. Object has both the data and the code. Object database should be used only when there is complex relationships between data and it should not be used when there are few tables with huge data. Its advantage is that the data model is based on the real world and its applications require less coding. The disadvantage of this type of DBMS is that it has less efficiency when the data is simpler. It is not commercially very successful because advantages did not rationalize the cost of converting billions of bytes of data to new format.
An object-relational database (ORD) is also known as object-relational database management system (ORDBMS). They were introduced in 1990s and they provide feasible solutions for handling complex data types. This database system has many features like polymorphism and inheritance and it also supports custom data types and methods. It combines the ability of object technology to handle the complex relationships and ORDBMS is very efficient if the data is complex and it has data independence.
The term Data Warehouse was coined by Bill Inmon in 1990. Data warehouse is a collection of data designed to support management decision making. It includes developing of system that extracts data from operating system. The term data warehousing commonly refers to the combination of many different databases across an entire enterprise. It is grouping of data from multiple sources into one easily manipulated database. To view day to day operations, companies may use data warehousing. Data warehousing is so rapidly growing in past few years such that now most of the companies have data warehouse. Data warehousing is normally used by larger companies to analyze larger sets of data. As they are separate from operational systems, they provide retrieval of data without slowing down operational systems and they can record historical information.
Databases are used in Web since 1990s and Web enabled database is a database with web based interface. Web designer and database designer need not to know each other designs. Web enabled database system allows user to get the information they need from central depository and its is very easy to interact with the web interface and they can be easily accessed where there is internet facility available and different privileges can be given to different users for example on LMS a teacher is allowed to upload but a student is only allowed to download but in web enabled database system it is quite possible that some outside user would get high level of access. It can also be used to make virtual community, where participants in distant locations can exchange ideas.
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