Can you name the types of keys used in database management systems?

In database management systems (DBMS), different types of keys are used for organizing and ensuring data integrity:

• Primary Key — a unique identifier for a record in a table. It cannot be NULL and must be unique.
• Foreign Key — a field or set of fields that references the primary key of another table, establishing a relationship between tables.
• Unique Key — guarantees the uniqueness of values in a column or a set of columns, but may allow NULLs (depending on the DBMS).
• Composite Key — a key consisting of multiple columns that together ensure the uniqueness of a record.
• Alternate Key — any unique key that is not the primary key.
• Surrogate Key — an artificial key, usually a numeric identifier, that does not carry business meaning.

These keys help maintain data integrity and optimize queries.