A business key is a unique identifier for a specific entity in a database. It is a combination of one or more attributes that can be used to uniquely identify an entity. Business keys are used to ensure data integrity and to facilitate data retrieval and manipulation.
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There are two main types of business keys:
- Primary key: A primary key is a mynewpinkbutton identifier for a single row in a table. It is the most important type of business key and is used to enforce the entity integrity constraint.
- Foreign key: A foreign key is a column that references the primary key of another table. It is used to establish a relationship between two tables.
Business keys are important for a number of reasons:
- Data integrity: Business keys help to ensure data integrity by preventing duplicate records from being created and by preventing invalid data from being entered into the database.
- Data retrieval: Business keys can be used to retrieve data quickly and efficiently. For example, if you need to retrieve all of the customers from a database, you can use the customer ID as the business key.
- Data manipulation: Business keys can be used to manipulate data easily and efficiently. For example, if you need to update the address of a customer, you can use the customer ID to identify the customer record that needs to be updated.
Here are some examples of business keys:
- Customer ID: A customer ID is a unique identifier for a customer in a customer database.
- Product ID: A product ID is a unique identifier for a product in a product database.
- Order ID: An order ID is a unique identifier for an order in an order database.
- Employee ID: An employee ID is a unique identifier for an employee in an employee database.
When choosing a business key, it is important to consider the following factors:
- Uniqueness: The business key must be unique for each row in the table.
- Non-nullability: The business key must not be null.
- Immutability: The business key should not be changed once it has been assigned.