Hi, need to submit a 1250 words paper on the topic Structured Query Language: History, and Usage. SQL is used in varied environments of client-server programming, web programming, and host-based database programming.
Knowledge about databases is a prerequisite to understanding SQL. The Webster’s Dictionary defines a database as ‘a usually large collection of data organized especially for rapid search and retrieval.’ Taken as such, a database could even not be associated with computers and simply be paper-based in the form of organized data on paper.
Databases are however closely associated with computers because computers represent the simplest, fastest, and most efficient way to store, manage, retrieve, and update data. Computer-based databases, which are the databases referred to in this paper, can range from the older Legacy mainframes often with the Virtual Storage Access Method (VSAM), dBase, and other file-based databases, the Relational DataBase Management Systems (RDBMS) and the recent XML and Object-oriented databases.
There have essentially been three types of database models – Hierarchical Databases, Network Databases, and Relational Databases. In the hierarchical model, the data is structured in what is known as a parent-child relationship. In this model, the basic logic hinges on the assumption that a child element can have only one parent, while a parent can have many children. This relationship in a database design is termed the ‘one-to-many’ relationship as opposed to the elementary ‘one-to-one’ where a single element can be linked only to another single element. The hierarchical model is nagged by the problem of data redundancy. The Network model was developed to eliminate this problem of redundancy. It represents data using set theory instead of a hierarchy. In this structure, a child element has more than one parent resulting in a child having many parents and a parent having many children in what is termed as the ‘many-to-many’ relationship. Both the hierarchical and network models had limitations. Their indexing systems are linked to the hard disk sectors in which the data resides. Moving the data across sectors leads to problems. Moreover, querying data from multiple tables requires sophisticated programming that uses proprietary languages.