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What primary key characteristics are considered desirable? Explain why each characteristic is considered desirable.
Database Systems: Design, Implemen...
Solutions
Database Systems: Design, Implemen...
What primary key characteristics are considered desirable? Explain why each characteristic is considered desirable.
Primary key (PK):
- To identify each record in a table, at least there must be one data field, which should be unique.
- That is corresponding data field of every record should be unique.
- It is called primary key.
- Primary key is used to identify the unique record from a collection of records.
Explanation of Solution
Characteristics of desirable primary key (PK):
A primary key characteristic consists of six types. They are:
- Unique values
- Nonintelligent
- No change over time
- Preferably single-attribute
- Preferably numeric
- Security-compliant
Explanation of desirable primary key characteristics:
Unique values:
Each entity instance is uniquely identified by the primary key. It must be able to security unique values and it can’t contain null values.
Nonintelligent:
The embedded semantic meaning can’t contain by the PK other than to uniquely identify every entity instance. Embedded semantic meaning attribute is possibly better used as an expressive characteristic of the entity compared to an identifier.
No change over time:
In this type of PK, if the attribute contains semantic meaning, then it possibly focuses to updates that are modification...
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