Data integrity - Data integrity is something we strive to have in our database. It refers to the concept of our data being accurate, up to date, not conflicting with other data, and clear as to what data belongs to what entity. So we don't just want random facts of information floating around without the ability to associate that data with the thing the data is about. Entity - The thing which the data is about. Attribute - The data that describes an entity. The entity becomes the table name and the attribute becomes a column of that table. How do we distinguish different rows? We need what is known as a primary key. Primary key - A column, or group of columns, that uniquely defines each row. Usually this is just a generated number that means nothing. This type of key is known as a surrogate key and is the most common kind of primary key. The other type of key is known as a natural key. An example of something that could be set up as a natural key is an email address. It could uniquely define a person. What do we do if we want to reference this primary key from another table? This introduces the concept of a foreign key, which we will be discussing in the next video. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me! www.patreon.com/calebcurry Subscribe to my newsletter: eepurl.com/-8qtH Donate!: bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: CalebCurry.com Facebook: www.facebook.com/CalebTheVideoMaker Google+: plus.google.com/+CalebTheVideoMaker2 Twitter: twitter.com/calebCurry Amazing Web Hosting - www.dreamhost.com/r.cgi?1487063 (The best web hosting for a cheap price!)

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