Okay, we've established that relational databases organize data into tables, and these tables have columns (or attributes) that define the type of information being stored, like a FirstName
, an EmailAddress
, or a ProductPrice
. But how do we store information about a specific person, email, or product? That's where rows come in.
Think of a table as a structured grid, similar to a spreadsheet. If the columns represent the categories of information (like Name
, Species
, Age
in a table about pets), then each row represents a single, complete entry or item within that category set. Each row holds the specific values for each column for one particular instance of the thing the table describes.
For example, consider a simple Pets
table:
PetID | Name | Species | Age |
---|---|---|---|
1 | Fido | Dog | 5 |
2 | Whiskers | Cat | 3 |
3 | Buddy | Dog | 8 |
In this table:
PetID
1, Name
Fido, Species
Dog, Age
5) represents one specific pet: Fido the dog.Each row contains a value for every column defined in the table structure (though sometimes a value might be explicitly marked as unknown or NULL
). This collection of values across a single row forms a complete unit of information about one particular entity.
You'll often hear the term record used synonymously with row. A record is essentially the information contained within a single row. It's a set of related data fields (the column values) treated as a unit. So, the first row in our Pets
table is the record for the pet named Fido.
Here's a visual representation:
A simple table structure showing columns (headers) and rows (records). The highlighted first row represents the complete record for the pet 'Fido'.
The concept is fundamental: columns define the structure, and rows provide the actual data, with each row representing one distinct item or entity that fits that structure. As we'll see shortly, ensuring each row is uniquely identifiable (like using the PetID
here) is a significant aspect of relational database design, leading us to the idea of primary keys. For now, focus on understanding that a row is a horizontal slice through the table, holding all the information about one specific thing the table is tracking.
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