Which of the following is found in one or more columns of data and contains a unique identifier for the row?answerRelationshipForeign keyAttributePrimary key

Break Down the Problem

1. Identify components of the question: The question is about understanding data concepts, specifically the unique identifier in a database or table structure.
2. Options provided: Relationship, Foreign key, Attribute, Primary key.

Relevant Concepts

1. Primary Key: This is a field (or combination of fields) in a table that uniquely identifies a row in that table. A primary key must contain unique values, and it cannot contain null values.
2. Foreign Key: This is a field (or fields) in one table that uniquely identifies a row of another table or the same table. It links two tables together.
3. Attribute: This is a column in a table that has a particular property or piece of information about the entity represented by that table.
4. Relationship: This refers to how two or more tables relate to each other in a relational database.

Analysis and Detail

• The question specifically asks for something that contains a unique identifier for rows.
• By definition, the Primary key fits this description accurately since it is created specifically to serve as a unique identifier for each record in a table.

Verify and Summarize

• The other options do not serve as unique identifiers directly. A Foreign key identifies a relationship with another table but does not inherently provide unique identification within its own table.
• An Attribute represents a characteristic of an entity, while a Relationship indicates how tables are connected.

Final Answer

The correct answer is Primary key, as it uniquely identifies each row in one or more columns of data.