First Normal Form Domain is atomic if its elements are considered to be indivisible units Examples of non-atomic domains: Set of names,composite attributes Identification numbers like CS101 that can be broken up into parts A relational schema R is in first normal form if the domains of all attributes of R are atomic Non-atomic values complicate storage and encourage redundant (repeated)storage of data Example:Set of accounts stored with each customer,and set of owners stored with each account We assume all relations are in first normal form (and revisit this in Chapter 9) Database System Concepts-5th Edition,Oct 5,2006 7.8 @Silberschatz,Korth and SudarshanDatabase System Concepts - 5 7.8 ©Silberschatz, Korth and Sudarshan th Edition, Oct 5, 2006 First Normal Form Domain is atomic if its elements are considered to be indivisible units Examples of non-atomic domains:  Set of names, composite attributes  Identification numbers like CS101 that can be broken up into parts A relational schema R is in first normal form if the domains of all attributes of R are atomic Non-atomic values complicate storage and encourage redundant (repeated) storage of data Example: Set of accounts stored with each customer, and set of owners stored with each account We assume all relations are in first normal form (and revisit this in Chapter 9)