Database Management System Relational Databases Computer Science Essay

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A database is a collection of information that is stored in a way that is easily saved, manipulated, queried, and updated. Due to the fact that there may be several databases in a company or organization, specific database management software is needed for these databases. Hence, the reason for database management system (DBMS). With DBMS, data is modified, retrieved, stored, deleted, and added by using software that allocate a computer to execute these database functions. The first DBMSs were created in 1960's because of the need for business to get rid of redundant and large amounts of information; As well as, the need to manipulate all of their stored data in a secure and safe way. There are several types of database models such as the flat model, hierarchal model, network model and relational model. Each serves a different type of purpose. It is said that the first relational database management system (RDMS) was created in the 1970, by a man name E.F. Codd, who worked for IBM at the time. However, there were a number of DBMS vendors, by the mid 1980's, who argued that their database management systems were relational database management systems. RDBMSs employ the relational model of relationships and tables in a database. The RDMS structure is, for the most part, the most frequently used structure today. It can be used by all computer systems, whether they are micro systems, midrange systems, or mainframe systems. RDMS uses two-dimensional columns and rows to store data and the records' tables can be connected by familiar key values. Some of the major RDMS vendors today, are Oracle, IBM, and Microsoft. Oracle released the original commercially available DBMS that used structured query language (SQL). IBM also released its own DBMS language named SQL, but it was different from Oracle's. However, Microsoft was late in the game to create its own RDMS. It was not until almost 1990 that Microsoft came out with its RDMS server and RDMS software based on SQL. There is a lot of history behind RDBMSs. The information on the history of RDBMSs takes readers from how they came about from the first DBMSs in the 1960's, and to the 1970's, 1980's, 1990's, and now. RDMS continue to develop for the better. The development of commercial, to the development of free, RDMSs has helped consumers in their use of databases and relational databases.

Before I can discuss the history of database management systems and relational database systems (RDMS), there are some things that must be brought up, such as what is a database? Why do we use databases? What is a relational database? Why do we need relational databases? What is a Database management system? Who created the first DBMS? Who created the first RDMS? Who created RDBMS next? What is the preference; Preformed DBMS or a DBMS that can be manipulated? How are DBMS used today? Will DBMS replace paper filing?

So, what is a database? A database is a well-structured gathering of data or information that is stored on a computer. The data in the database must be easy to access, change, and added, or removed. The database must be able to store small amounts of data or extremely large amounts of data, depending on the type and use of the database. For large databases, a DBMS is needed in order to manage the data and queries in the databases because if the database is large enough and used by many people, there will most likely be more than one type of database. For instance, Company A may have several databases: employee-training database, finance database, revenue database, insurance database, and so on, but it would take a DBMS to manage the databases. Of course, some of the other important features of a DBMS are to secure the databases by backing up and by authentications. Before databases, 1968, files were maintained in flat files, "Requires extensive programming in third-generation language such as COBOL, BASIC. Limitations: Separation and isolation: Each program maintains its own set of data, users of one program may not aware of holding or blocking by other programs. Duplication: Same data is held by different programs, thus, wastes space and resources. High maintenance costs such as ensuing data consistency and controlling access. Sharing granularity is very coarse and there is weak security" (CompHist.org. 2004).

The first computer database was invented in the 1960s. Charles Bachman worked for Dow Chemical stating in the 1950s and after moving up the ladder to Data Processing Manager, Bachman moved to New York to work for General Electric (GE) in 1960. It is when he worked for GE that he developed one of the very first DBMS, known as Integrated Data Store (IDS). He then moved on to a company called Cullinet and created a version of the IDS labeled, IDMS, which support IBM mainframes. IDS and IDMS are network database models, while the IMS is a hierarchal database model. IBM developed the Information Management System (IMS) in 1968. According to Kim Moutsos, "ICS is installed, and on August 14, the first "IMS READY" message is displayed on an IBM 2740 terminal at the Rockwell Space Division in Downey, Calif." (Moutsos, K. 2008). ICS was the original name for IMS, which changed to IMS between 1969 and 1970. ICS was needed for the Apollo space mission to help manage the huge amount of bills for the supplies needed to construct the Apollo spacecraft. In 1970, the first relational database was created.

Why do we need a database? We can live without databases, but it would definitely be hard to store and access data without a database. All of the information in a database can be saved in a word document, in folders saved in a safe, or even in spreadsheets. However, it would not be beneficial to a company, large or small, to not have some sort of database, or way to save important information. Databases make it easy on anyone accessing a database, such as a bank teller accessing a customer's bank account information from any branch office, or a dental office accessing a customer's dental records without the actual physical dental records that may have been lost. The CEO can look at a database and find out how many people work for him/her, the names, ages, addresses, marital status, hourly wage, average sick days, etc...on any of his employees, if he/she had the proper access to the employee database. If this information was saved in an excel spread sheet, he may have to ask an employee to come up with all of this data and it may take the employee hours or days to find all of this information. Then imagine if the CEO asked this employee, after he did all of the hard work, the CEO said that he wanted to know the birth date of each employee. This would definitely cause an issue, especially if the employee had to find all of the information from file folders, and still time consuming if all of the information were in spreadsheets, searching for each name and the rest of the information. Is it possible to use a spread sheet? Yes. However, it would not be wise, when all of the information could be given by accessing a database, even if the employee had to run a few queries himself, it would be faster. Not only that, what if there was other information in the spread sheet or file folder about an employee that no one but the CEO or boss should know? Such as bankruptcy information or medical information. If this information is in a spread sheet or file folder, then it would definitely be easier to access than with a database that could deny this employee information to other employee's personal information.

The flat model is a two-dimensional collection of data. In a flat model database, there is usually one column of information and within that column; each item is related to the other. A flat model data could include the amount of monthly bills and for the bills column, each row will only contain a bill amounts. Such as this:

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The hierarchical model database is similar to a tree like organization. In a hierarchical model database, all access to information or data goes from the top of the hierarchy and are accessed downward. For instance, a hierarchal database of managers, may catalog each manager as a separate file. Inside these file are all of the employees of the managers. Such as this:

Emp #

Designation

Reports To

100

PM

 

101

Dev Lead

100

102

Test Lead

100

103

Team Member

101

Fig. 1. Hierarchal Model

In a network model, each record is stored with a specific link to other records; thus the name network model. Figure 2 is an example of a network database model that I took from the Internet:

Fig. 2. Network database example (SQLBible. n.d).

The relational database model is the most important model to this paper and the reason for this paper. The relational database model was developed by E.F. Codd. It allows the following: storage and access to data, defines the structure of data, and provides constraints of data integrity. The relations between data in the database are properly organized in tables, which are collections of records.

An example of relational model tables from Gilfillan, Ian:

Poet

Code

First Name

Surname

Age

1

Mongane

Afrika

62

2

Stephen

Serote

58

3

Tatumkhulu

Watson

29

Fig. 3a

Poem

Title

Poet

Wakening Night

1

Thrones of Darkness

2

Once

3

Fig. 3b

In the figures, Codes are relational to Poet. In the Poet table, Code 1 is Mongane Afrika, aged 62. This author wrote Wakening Night, according to the tables because in the Poem table, Poet 1 is equivalent to Code 1 in the Poet table.

How do we incorporate all of the databases that we may use? We do this by using database management systems (DBMS). "A database management system (DBMS) is the software that allows a computer to perform database functions of storing, retrieving, adding, deleting, and modifying data. Relational database management systems (RDBMS) implement the relational model of tables and relationships" (Chapple, M. 2010). A DBMS is a compilation of software programs. These software programs manipulate bulky, compilations of data to be managed, modified, and stored in many different ways. Additionally, a DBMS is liable for the integrity of the database. The DBMS ensures that only one person can modify the very same records at the very same time, as well as avoiding replicated entries, such as two invoices getting the same invoice number. A DBMS should have a interface in order to add data, update data, and query data, as well allow concurrent users, access control, reliable storage, and efficient recovery from database crashes.

What are some types of DBMS software? There are several names or brands of DBMS software accessible for purchase. A few of the most popular are MySQL, Oracle, Microsoft Access, FileMaker, and Microsoft SQL. As a database user and someone who has learned to create small databases since the early 1990's, I have only used three database products. I learned dBase III when I first joined the Army because I was a programmer at the time. However, I only used it for approximately one year and never got into databasing until 1998 and 2004, when I learned Microsoft Access in school. Still, it was not until the last five years did I really use databases. I use Microsoft Access, but the larger databases in use by my unit right now are Oracle databases. As a person who no longer programs, Oracle definitely scares me because of the knowledge needed to create and run the Oracle databases. Therefore, for someone who would only create databases for home or personal use, I will stick with Microsoft Access. Of course, having said all of that, it is not true that I rarely use databases. I have used databases for years. My online banking is accessed through a database, my medical records are accessed through a database, and even my dog's veterinary records are accessed through a database that I access on the portal.

Who created the first RDMS? As stated earlier, a relational database is comprised of a compilation of tables. These tables accumulate and save specific data sets. It is said that the first relational database management system (RDMS) was created in the 1970, by a man name E.F. Codd, who worked for IBM at the time.

Who created the follow on RDBMSs? There were a number of DBMS vendors, by the mid 1980's, who argued that their database management systems were relational database management systems. RDBMSs employ the relational model of relationships and tables in a database. "Oracle Corporation created the first commercial relational database in 1979. IBM followed suit in 1982 with the SQL Data System. Microsoft was the last major company to jump in with SQL Server 4.2 in 1992. Oracle and Microsoft have the overwhelming market share of commercial database products in use, and will likely continue to dominate the market in the years to come" (Powell, K. 2010).

Why do we need relational databases? Well, it is pretty easy to understand why we need RDBMS. The RDMS structure is, for the most part, the most frequently used structure today. It can be used by all computer systems, whether they are micro systems, midrange systems, or mainframe systems. RDMS uses two-dimensional columns and rows to store data and the records' tables can be connected by familiar key values. Some of the major RDMS vendors today, are Oracle, IBM, and Microsoft. Oracle released the original commercially available DBMS that used structured query language (SQL). IBM also released its own DBMS language named SQL, but it was different from Oracle's. However, Microsoft was late in the game to create its own RDMS. It was not until almost 1990 that Microsoft came out with its RDMS server and RDMS software based on SQL.


References:

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Author Unknown (n.d.). SQL Bible. Network Databases (Fig. 2). Retrieved February 17,

           2010, from http://www.tar.hu/sqlbible/sqlbible0011.html#wbp05Chapter1P92

Chapple, M. (2010). About.com. Databases. Retrieved February 17, 2010, from

           http://databases.about.com/od/administration/g/dbms.htm

CompHist.org. (2004). Learning Computer History. A Brief History of Databases.

            Retrieved February 10, 2010, from http://comphist.org/

computing_history/new_page_9.htm

Gilfillan, I. (2002). Internet.com. Relational Database Model. (Fig. 3a & 3b). Retrieved            February 12, 2010, from http://www.databasejournal.com/sqletc/article.php/

1469521/Introduction-to-Relational-Databases.htm

Moutsos, K. (2008). IBM. IMS at 40: Stronger than ever. Retrieved February 10, 2010,

           from http://www.computer.org/portal/web/csdl/doi/10.1109/MAHC.2009.126

Powell, K. (2010). PowerGeek.com. What is a Relational Database? Retrieved February

           8, 2010, from http://www.wisegeek.com/what-is-a-relational-database.htm

Toolbox.com. (2010). Hierarchal Database. (Fig. 1) Retrieved February 17, 2010, from

            http://it.toolbox.com/wiki/index.php/Hierarchical_Database