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Book Overview & Buying
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Table Of Contents
The Applied SQL Data Analytics Workshop - Second Edition
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A relational database is a database that utilizes the relational model of data. The relational model, invented by Edgar F. Codd in 1970, organizes data as relations, or sets of tuples. Each tuple consists of a series of attributes that generally describe the tuple. For example, we could imagine a customer relationship where each tuple represents a customer. Each tuple would then have attributes describing a single customer, giving information such as the last name, first name, and age, perhaps in the format (Smith, John, 27). One or more of the attributes is used to uniquely identify a tuple in a relation and is called the relational key. The relational model then allows logical operations to be performed between relations.
In a relational database, relations are usually implemented as tables, as in an Excel spreadsheet. Each row of the table is a tuple, and the attributes are represented as columns of the table. While not technically required, most...