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Computer Science steps such as synthesis (creating new designs) or decomposition (improving existing
designs). This approach reduces redundancy, anomalies, and inconsistencies while
enforcing proper dependency constraints on attributes and tables to maintain data
integrity.

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For instance, normalization prevents anomalies like an employee with ID 426 having
different addresses across multiple records, as seen in Table 8.5.

Table 8.5: Data anomalies

Employees’ Skills
Employee ID Employee Address Skill

426 Box 137 MWANZA Public speaking
426 Box 132 MWANZA Typing

645 Box 8991 Dar es salaam Carpentry
645 Box 8991 Dar es salaam Public speaking

In this example, the same answers to this particular employee’s address,

information can be expressed affecting the database’s use and effectiveness.
on multiple rows; therefore,
updates to the relationship may (b) Database normalisation forms
result in logical inconsistencies. Normalization is a methodical process that
For example, each record in an follows clear rules at each stage of data
“Employees’ Skills” relation modeling. It involves various normal forms,
might contain an Employee ID, each with specific criteria. The primary normal
forms include First Normal Form (1NF), Second
Employee Address, and Skill; Normal Form (2NF), and Third Normal Form
thus, a change of address for a (3NF). These forms are designed to remove
particular employee may need anomalies such as insertion, updating, and
to be applied to multiple records deletion issues once applied to a dataset.
(one for each skill). If the update
is only partially successful, (the Additionally, there is the Un-Normalized
employee’s address is updated Form (UNF), which represents the starting

on some records but not others), point before applying normalization rules.
then the relation is left in an It serves as the initial stage before detailed
inconsistent state. Specifically, descriptions of the common normal forms
the relation provides conflicting (1NF, 2NF, and 3NF) are discussed, as
illustrated in Figure 8.17.

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