08. Quiz: Primary - Foreign Key Relationship
Helpful ERD For Answering the Below Questions
QUIZ QUESTION::
Match the appropriate definition or description to each term or column.
ANSWER CHOICES:
Definition or Column Description |
Term or Column |
---|---|
Has a unique value for every row in that column. There is one in every table. |
|
The link to the primary key that exists in another table. |
|
The primary key in every table of our example database. |
|
A foreign key that exists in both the web_events and orders tables. |
|
The ON statement associated with a JOIN of the web_events and accounts tables. |
SOLUTION:
Definition or Column Description |
Term or Column |
---|---|
The link to the primary key that exists in another table. |
|
A foreign key that exists in both the web_events and orders tables. |
|
The primary key in every table of our example database. |
|
The ON statement associated with a JOIN of the web_events and accounts tables. |
|
Has a unique value for every row in that column. There is one in every table. |
SOLUTION:
- There is one and only one of these columns in every table.
- They are a column in a table.
SOLUTION:
- They are always linked to a primary key.
- In the above database, every foreign key is associated with the crow-foot notation, which suggests it can appear multiple times in the column of a table.