What represents the unique identifier for a record in an attribute table?

A unique identifier for a record in an attribute table is known as a key. This key is a specific field within the attribute table that holds a unique value for each record, allowing for efficient identification and retrieval of that record. The use of a key is essential for maintaining data integrity, as it ensures that each record can be distinctly recognized even in large datasets. Keys are particularly important in relational databases where they help establish relationships between different tables.

In contrast, "field" refers to a column within the attribute table and contains data about a specific attribute, but not all fields serve as unique identifiers. "Row" indicates a single record in the table, which can include multiple fields but does not directly denote a unique identifier. "Attribute" pertains to the specific pieces of data contained within a field, again not sufficient on its own to represent a unique identifier. Thus, the concept of a key encapsulates the necessary function to uniquely identify records in an attribute table effectively.