Relational database is a database system where the information is stored as a relational model of data. This means that you can store and retrieve data without knowing all the back end coding for the data. This method was created by E. F. Codd back in 1970 and has been widely used to this day. To further simplify relational databases. If you have a table with two columns in it and you wanted to change the one of those columns then it would delete the entire table without a relational database. With a relational database it would store those columns as two separate tables and then will allow you to manipulate columns individually without having to delete the whole table. Structured Query Language or SQL is the language used in most relational databases. SQL became the standard language to use back in 1986 and was developed in the 70's by Donald Chamberlin and Raymond Boyce.
The relational database is built in two different stages, the logical data model is created first and then the physical data model is created afterwards. The logical data model allows you to create a layout for the design of the entire database itself. The physical data model creates the data tables themselves and the columns and rows. These databases use key terms to define the tables. Entity is information that is needed from the real world and the information topic that you want to store data on. The attribute is used to detail information about a certain entity instance or some information that you want to track. A primary key is used to identify certain entities which means that every entity will have a different primary key. A primary key can be one attribute or it can contain several depending on what the user wishes and the values in the primary key have to have a value in them they can never be blank. Before relational databases they used tab delimited files. These differed from relational databases because every entry is separated by certain characters. This causes each entry to contain many pieces of information in it.
References:
https://en.wikipedia.org/wiki/Relational_database
https://en.wikipedia.org/wiki/SQL
http://www.dummies.com/how-to/content/knowing-just-enough-about-relational-databases.html
http://computer.howstuffworks.com/question599.htm
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Derek-
ReplyDeleteI had no clue as to how relational databases worked, but the column example that you gave clarified it pretty well. You also made it clear how databases function internally and why they are able to store such large amounts of data. The abilities of this type of software seem to be endless, but there still seems to be progress made almost every day in this field. Interesting post.