What Primary Key Prevents Duplicate Records in Databases?
Learn about primary keys that ensure no duplicate records in your database, enhancing data integrity.
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The primary key that ensures no duplicate records is typically an auto-incrementing ID or a unique identifier (UUID) field. Assigning a unique value to each record in your database guarantees that each entry is distinct, thus preventing duplicates and maintaining data integrity.
FAQs & Answers
- What is the purpose of a primary key in a database? The purpose of a primary key in a database is to uniquely identify each record in a table, ensuring that no two records have the same key value, which helps maintain data integrity and allows for efficient data retrieval.
- How does an auto-incrementing ID work? An auto-incrementing ID is a type of primary key that automatically generates a unique sequential number each time a new record is added to the database, ensuring each entry has a distinct identifier.
- What are the differences between a primary key and a unique key? While both primary and unique keys ensure that values are unique within a column, a primary key does not allow null values and uniquely identifies a record, whereas a unique key allows for one null value in the column.
- Can a primary key have multiple columns? Yes, a primary key can consist of multiple columns, known as a composite key, which collectively ensures uniqueness for each record across the combination of the specified columns.