To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) It is a primary key for a Dimension table - This option is incorrect. A surrogate key is not specifically a primary key for a Dimension table. It can be used as a primary key, but it is not limited to that role.
Option B) It is a system-generated sequence number - This option is correct. A surrogate key is a unique identifier that is generated by the system, typically using a sequence number or an auto-incrementing value. It is used to uniquely identify records in a table and is not derived from any meaningful data.
Option C) It is a unique key - This option is partially correct. A surrogate key is indeed a unique key, but its uniqueness is achieved by being generated by the system rather than being inherently unique based on the data it represents.
Option D) It is a foreign key for a FACT table - This option is incorrect. A surrogate key is not specifically a foreign key for a FACT table. While it can be used as a foreign key, it is not limited to that role.
The correct answer is B) It is a system-generated sequence number. This option is correct because a surrogate key is a unique identifier generated by the system, typically using a sequence number or an auto-incrementing value, to uniquely identify records in a table.