Computer database in which all data is stored in Relations which to the user are tables with rows and columns. Each table is composed of records called Tuples and each record is identified by a field attribute containing a unique value. These relationships allow the database user to access the data in almost an unlimited number of ways, and to combine the tables as building blocks to create complex and very large databases.
Under the relational model, accessing data in a database does not require navigating a rigid pathway through a tree or hierarchy. Users can query any table in the database, and combine related tables using special join functions to include relevant data contained in other tables in the results. Results can be filtered based on the content of any column, and on any number of columns, allowing users to easily retrieve meaningful results. Users can choose which columns to include in the results so that only relevant data are displayed.
One disadvantage of relational databases is the expensive of setting up and maintaining the database system. If you want to set up a relational database, you generally need to purchase special software. If you are not a programmer, you can use any number of products to set up a relational database. It does take time to enter in all the information and set up the program. If your company is large and you need a stronger database, you will need to hire a programmer to create a relational database using Structured Query Language (SQL) and a database administrator to maintain the database once it is built. No matter the size of your company, if you store legally confidential or protected information in your database such as health information, social security numbers or credit card numbers, you will also have to secure your data against unauthorized access to meet regulatory standards.
Relational database has many features such as type, attribute, tuple, relations, etc.
A type is a set of values and related operators.
An attribute is a name, value, type triple.
A tuple is a set of attributes.
A relation is a set of tuples with a given heading.