From the course: Relational Databases Essential Training
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Required attributes and null values
From the course: Relational Databases Essential Training
Required attributes and null values
- [Instructor] When entering records into a database, it's not a requirement that every attribute column is populated with data. When a value isn't supplied, it's said to be null. A null value represents data that's unspecified, unknown, or not applicable. It's important not to confuse null with zero, or a blank space character. Null means literally nothing at all or no data. Let's take a look at this data table of people and their birthdays. Antonio's birthday is currently null. That doesn't mean that he doesn't have a birthday. He most certainly does. All we can say about it is that it's currently not known, and any information about it is missing from the database. Null values are important when you start thinking about whether information in a column is required to be supplied for every record. Maybe this data table represents customers and you've offered to send a special coupon to people on their birthday. Some…
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