Learn about the fundamental concepts of databases, why, how, and when they're used.

Fundamentals of Web Programming

Databases are universal - they underlie the technology you use every day. They're a crucial component of everything from telecommunications systems, banking systems, and video games to just about any other software system that maintains some amount of persistent data.

In this module, you'll learn about the fundamental concepts of databases, why and when they're used, what relational databases are, and entity-relationship diagrams. You will also be exposed to techniques like normalization that help to increase the efficiency of databases.

Database Fundamentals

The values of a column are of the same data-type.

Which of the following is NOT a property of tables?

<p>Which of the following is NOT a property of tables?</p>


We can arbitrarily choose any super key to be the candidate key.

What is the difference between a super key and a candidate key?

<p>What is the difference between a super key and a candidate key?</p>


Which of the following constraints is being violated in the table below?


<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>

<table style="width:100%">
  <tr>
    <th><u>Customer_Id</u></th>
    <th>Name</th> 
    <th>Item_Ordered</th>
  </tr>
  <tr>
    <td>1 </td>
    <td>Brandon </td>
    <td>Shoes   </td>
  </tr>
  <tr>
    <td>2</td>
    <td>Don</td>
    <td>Shirts</td>
  </tr>
  <tr>
    <td>3</td>
    <td>Jeff</td>
    <td>Laptop</td>
  </tr>
  <tr>
    <td>4</td>
    <td>Jack</td>
    <td>Smartphone</td>
  </tr>
  <tr>
    <td>3</td>
    <td>Jeff</td>
    <td>TV</td>
  </tr>
</table>

</body>
</html>


<p>Which of the following constraints is being violated in the table below?</p>
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>
<table style="width:100%">
  <tr>
    <th><u>Customer_Id</u></th>
    <th>Name</th> 
    <th>Item_Ordered</th>
  </tr>
  <tr>
    <td>1 </td>
    <td>Brandon </td>
    <td>Shoes   </td>
  </tr>
  <tr>
    <td>2</td>
    <td>Don</td>
    <td>Shirts</td>
  </tr>
  <tr>
    <td>3</td>
    <td>Jeff</td>
    <td>Laptop</td>
  </tr>
  <tr>
    <td>4</td>
    <td>Jack</td>
    <td>Smartphone</td>
  </tr>
  <tr>
    <td>3</td>
    <td>Jeff</td>
    <td>TV</td>
  </tr>
</table>
</body>
</html>


Which of the following constraints is being violated in the tables below?

Customer Table

<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>

<table style="width:100%">
  <tr>
    <th><u>Customer_Id</u></th>
    <th>Name</th> 
    <th>Order_Id</th>
  </tr>
  <tr>
    <td>1 </td>
    <td>Brandon </td>
    <td>102  </td>
  </tr>
  <tr>
    <td>2</td>
    <td>Don</td>
    <td>234</td>
  </tr>
  <tr>
    <td>3</td>
    <td>Jeff</td>
    <td>867</td>
  </tr>
  <tr>
    <td>4</td>
    <td>Jack</td>
    <td>420</td>
  </tr>
</table>

</body>
</html>


<br></br>


Order Table

<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>

<table style="width:100%">
  <tr>
    <th><u>Order_Id</u></th>
    <th>Item_Name</th> 
    <th>Item_Category</th>
  </tr>
  <tr>
    <td>102 </td>
    <td>Shoes </td>
    <td>Clothing  </td>
  </tr>
  <tr>
    <td>234</td>
    <td>Shoes</td>
    <td>Clothing</td>
  </tr>
  <tr>
    <td>420</td>
    <td>Laptop</td>
    <td>Electronics</td>
  </tr>
  <tr>
    <td>390</td>
    <td>TV</td>
    <td>Electronics</td>
  </tr>
    <tr>
    <td>111</td>
    <td>Smartphones</td>
    <td>Electronics</td>
  </tr>
</table>

</body>
</html>




<p>Which of the following constraints is being violated in the tables below?</p>
<p>Customer Table</p>
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>
<table style="width:100%">
  <tr>
    <th><u>Customer_Id</u></th>
    <th>Name</th> 
    <th>Order_Id</th>
  </tr>
  <tr>
    <td>1 </td>
    <td>Brandon </td>
    <td>102  </td>
  </tr>
  <tr>
    <td>2</td>
    <td>Don</td>
    <td>234</td>
  </tr>
  <tr>
    <td>3</td>
    <td>Jeff</td>
    <td>867</td>
  </tr>
  <tr>
    <td>4</td>
    <td>Jack</td>
    <td>420</td>
  </tr>
</table>
</body>
</html>
<p><br></br></p>
<p>Order Table</p>
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>
<table style="width:100%">
  <tr>
    <th><u>Order_Id</u></th>
    <th>Item_Name</th> 
    <th>Item_Category</th>
  </tr>
  <tr>
    <td>102 </td>
    <td>Shoes </td>
    <td>Clothing  </td>
  </tr>
  <tr>
    <td>234</td>
    <td>Shoes</td>
    <td>Clothing</td>
  </tr>
  <tr>
    <td>420</td>
    <td>Laptop</td>
    <td>Electronics</td>
  </tr>
  <tr>
    <td>390</td>
    <td>TV</td>
    <td>Electronics</td>
  </tr>
    <tr>
    <td>111</td>
    <td>Smartphones</td>
    <td>Electronics</td>
  </tr>
</table>
</body>
</html>


Would the following INSERT operation violate any integrity constraint?

Operation: Insert <5, "Jack Ryan", "2300 Mcfarland Blvd, Northport, AL", 21, 3> into STUDENT.

Student Table

<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>

<table style="width:100%">
  <tr>
    <th><u>Student_Id</u></th>
    <th>Name</th> 
    <th>Address</th>
    <th>Age</th>
    <th>Class</th>
  </tr>
  <tr>
    <td>1</td>
    <td> Chloe Carter</td>
    <td> 777 Brockton Avenue, Abington, MA  </td>
     <td> 22 </td>
    <td>Senior </td>
  </tr>
   <tr>
    <td>2</td>
    <td> Neil Drukmen</td>
    <td> 3018 East Ave, Central Square, NY </td>
     <td>  20  </td>
    <td>Sophomore</td>
  </tr>
  <tr>
    <td> 3 </td>
    <td> Randy Pitchford</td>
    <td> 80 Town Line Rd, Rocky Hill, CT </td>
     <td> 21</td>
    <td> Junior </td>
  </tr>
   <tr>
    <td> 4 </td>
    <td>Kyle Boseman</td>
    <td> 5710 Mcfarland Blvd, Northport, AL</td>
     <td>  22 </td>
    <td>Senior </td>
  </tr>
</table>

</body>
</html>



<p>Would the following INSERT operation violate any integrity constraint?</p>
<p>Operation: Insert &lt;5, “Jack Ryan”, “2300 Mcfarland Blvd, Northport, AL”, 21, 3&gt; into STUDENT.</p>
<p>Student Table</p>
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>
<table style="width:100%">
  <tr>
    <th><u>Student_Id</u></th>
    <th>Name</th> 
    <th>Address</th>
    <th>Age</th>
    <th>Class</th>
  </tr>
  <tr>
    <td>1</td>
    <td> Chloe Carter</td>
    <td> 777 Brockton Avenue, Abington, MA  </td>
     <td> 22 </td>
    <td>Senior </td>
  </tr>
   <tr>
    <td>2</td>
    <td> Neil Drukmen</td>
    <td> 3018 East Ave, Central Square, NY </td>
     <td>  20  </td>
    <td>Sophomore</td>
  </tr>
  <tr>
    <td> 3 </td>
    <td> Randy Pitchford</td>
    <td> 80 Town Line Rd, Rocky Hill, CT </td>
     <td> 21</td>
    <td> Junior </td>
  </tr>
   <tr>
    <td> 4 </td>
    <td>Kyle Boseman</td>
    <td> 5710 Mcfarland Blvd, Northport, AL</td>
     <td>  22 </td>
    <td>Senior </td>
  </tr>
</table>
</body>
</html>


Would the following DELETE operation violate any integrity constraint?

Operation: Delete the STUDENT tuple with Student_Id = 2.


Student Table

<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>

<table style="width:100%">
  <tr>
    <th><u>Student_Id</u></th>
    <th>Name</th> 
    <th>Address</th>
    <th>Age</th>
    <th>Class</th>
  </tr>
  <tr>
    <td>1</td>
    <td> Chloe Carter</td>
    <td> 777 Brockton Avenue, Abington, MA  </td>
     <td> 22 </td>
    <td>Senior </td>
  </tr>
   <tr>
    <td>2</td>
    <td> Neil Drukmen</td>
    <td> 3018 East Ave, Central Square, NY </td>
     <td>  20  </td>
    <td>Sophomore</td>
  </tr>
  <tr>
    <td> 3 </td>
    <td> Randy Pitchford</td>
    <td> 80 Town Line Rd, Rocky Hill, CT </td>
     <td> 21</td>
    <td> Junior </td>
  </tr>
   <tr>
    <td> 4 </td>
    <td>Kyle Boseman</td>
    <td> 5710 Mcfarland Blvd, Northport, AL</td>
     <td>  22 </td>
    <td>Senior </td>
  </tr>
</table>

</body>
</html>

<p>Would the following DELETE operation violate any integrity constraint?</p>
<p>Operation: Delete the STUDENT tuple with Student_Id = 2.</p>
<p>Student Table</p>
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>
<table style="width:100%">
  <tr>
    <th><u>Student_Id</u></th>
    <th>Name</th> 
    <th>Address</th>
    <th>Age</th>
    <th>Class</th>
  </tr>
  <tr>
    <td>1</td>
    <td> Chloe Carter</td>
    <td> 777 Brockton Avenue, Abington, MA  </td>
     <td> 22 </td>
    <td>Senior </td>
  </tr>
   <tr>
    <td>2</td>
    <td> Neil Drukmen</td>
    <td> 3018 East Ave, Central Square, NY </td>
     <td>  20  </td>
    <td>Sophomore</td>
  </tr>
  <tr>
    <td> 3 </td>
    <td> Randy Pitchford</td>
    <td> 80 Town Line Rd, Rocky Hill, CT </td>
     <td> 21</td>
    <td> Junior </td>
  </tr>
   <tr>
    <td> 4 </td>
    <td>Kyle Boseman</td>
    <td> 5710 Mcfarland Blvd, Northport, AL</td>
     <td>  22 </td>
    <td>Senior </td>
  </tr>
</table>
</body>
</html>

Would the following UPDATE operation violate any integrity constraint?

Operation: Update the `Student_Id` of the STUDENT tuple with `Student_Id` = 4 to 1.


Student Table

<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>

<table style="width:100%">
  <tr>
    <th><u>Student_Id</u></th>
    <th>Name</th> 
    <th>Address</th>
    <th>Age</th>
    <th>Class</th>
  </tr>
  <tr>
    <td>1</td>
    <td> Chloe Carter</td>
    <td> 777 Brockton Avenue, Abington, MA  </td>
     <td> 22 </td>
    <td>Senior </td>
  </tr>
   <tr>
    <td>2</td>
    <td> Neil Drukmen</td>
    <td> 3018 East Ave, Central Square, NY </td>
     <td>  20  </td>
    <td>Sophomore</td>
  </tr>
  <tr>
    <td> 3 </td>
    <td> Randy Pitchford</td>
    <td> 80 Town Line Rd, Rocky Hill, CT </td>
     <td> 21</td>
    <td> Junior </td>
  </tr>
   <tr>
    <td> 4 </td>
    <td>Kyle Boseman</td>
    <td> 5710 Mcfarland Blvd, Northport, AL</td>
     <td>  22 </td>
    <td>Senior </td>
  </tr>
</table>

</body>
</html>

<p>Would the following UPDATE operation violate any integrity constraint?</p>
<p>Operation: Update the <code>Student_Id</code> of the STUDENT tuple with <code>Student_Id</code> = 4 to 1.</p>
<p>Student Table</p>
<!DOCTYPE html>
<html>
<head>
<style>
table, th, td {
  border: 1px solid black;
  border-collapse: collapse;
}
</style>
</head>
<body>
<table style="width:100%">
  <tr>
    <th><u>Student_Id</u></th>
    <th>Name</th> 
    <th>Address</th>
    <th>Age</th>
    <th>Class</th>
  </tr>
  <tr>
    <td>1</td>
    <td> Chloe Carter</td>
    <td> 777 Brockton Avenue, Abington, MA  </td>
     <td> 22 </td>
    <td>Senior </td>
  </tr>
   <tr>
    <td>2</td>
    <td> Neil Drukmen</td>
    <td> 3018 East Ave, Central Square, NY </td>
     <td>  20  </td>
    <td>Sophomore</td>
  </tr>
  <tr>
    <td> 3 </td>
    <td> Randy Pitchford</td>
    <td> 80 Town Line Rd, Rocky Hill, CT </td>
     <td> 21</td>
    <td> Junior </td>
  </tr>
   <tr>
    <td> 4 </td>
    <td>Kyle Boseman</td>
    <td> 5710 Mcfarland Blvd, Northport, AL</td>
     <td>  22 </td>
    <td>Senior </td>
  </tr>
</table>
</body>
</html>

---
Congratulations! You have reached the end of this chapter. At this point, you should be comfortable with ideas such as keys, constraints, and operations regarding relational databases.  

In the next chapter, we will tackle the concepts behind functional dependencies. 

This quiz will test your knowledge of relational databases.

Before We Begin

Fundamental Concepts

Data Modeling

Entity-Relationship Data Model

The Relational Data Model

Functional Depedencies

Normalization

Types of Databases

Conclusion

Quiz!