What is the primary focus of domain constraints in a database?

Domain constraints are a fundamental aspect of database design that specify the permissible values that an attribute can take. Their primary focus is to ensure data integrity by restricting the possible inputs for a field to a defined set, which can be based on data types, value ranges, or even specific lists of acceptable values. For instance, a domain constraint might dictate that a "Date of Birth" field must contain dates that fall within reasonable limits, or that an "Email" field must follow a specific format.

By doing so, domain constraints help maintain the accuracy and consistency of the data stored within the database. This prevents invalid data from being entered, which could lead to data corruption or unreliable analyses. In summary, domain constraints play a crucial role in defining the attributes' allowed values, thereby safeguarding the quality of the data.