January 2019
Beginner
556 pages
14h 19m
English
Content preview from Learning PostgreSQL 11 - Third Edition
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Domain integrity constraint
The domain integrity constraint ensures data validity. The first step in defining the domain integrity constraint is to determine the appropriate data type. The domain data types could be an integer, real, boolean, character, text, inet, and so on. For example, the data type of the first name and email address is text. After specifying the data type, check constraints, such as the mail address pattern, need to be defined:
- Check constraint: A check constraint can be applied to a single attribute or a combination of many attributes in a tuple. Let's assume that the customer_service schema is defined as customer_id, service_id, start_date, end_date, and order_date. For this relation, we can have a check constraint ...
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