Questions to ask a SQL Server database developer applicant

Are you a Database Administrator? Need to update DBA technical knowledge or need to prepare for a job interview? Check out this collection of Questions to ask a SQL Server database developer applicant...

Can you give me an overview of some of the database objects available for use in SQL Server 2000?
What is an index? What types of indexes are available in SQL Server 2000?
What does NULL mean?
What is a primary key? What is a foreign key?
What are triggers? What are the different types of triggers in SQL Server 2000?
How can you ensure that a table named TableB with a field named Fld1 will only have those values in the Fld1 field that are also in the table named TableA with a field named Fld1?
What is a performance consideration of having too many indexes on a production online transaction processing (OLTP) table?
What can be used to ensure that a field in a table only accepts a certain range of values?
What is the difference between a return parameter and an OUTPUT parameter?
What is a correlated sub-query? How can these queries be useful?