Transitive dependency
A transitive dependency is a dependency reached indirectly through one or more intermediate dependencies rather than declared or connected directly.
100 SQL Server Mistakes and How to Avoid Them
A transitive dependency occurs when a non-key attribute depends on another non-key attribute rather than directly on the key.
- How it is used
- Uses 3NF to identify attributes determined by nonprime attributes and separate them into related relations.
- How deep it goes
- Defines nontransitive dependence and demonstrates several relation splits, without formal dependency notation or algorithms.
- Examples
- Uses product type descriptions, salespeople, sales areas, customers, and customer contacts as dependency examples.
- What you can do after
- Apply it by decomposing relations and reconnecting them through foreign keys when nonprime attributes identify other attributes.
Read how 100 SQL Server Mistakes and How to Avoid Them explains transitive dependency →
Grokking Relational Database Design
A transitive dependency is a functional dependency in which a nonkey attribute depends on another nonkey attribute that depends on a key.
- How it is used
- Uses transitive dependencies to check database tables against 3NF and BCNF requirements.
- How deep it goes
- Defines the dependency chain, explains its anomalies, and demonstrates decomposition with foreign keys; it stops short of later normal forms.
- Examples
- Uses employee-department data and a purchase-payment_method-user relationship to expose direct and indirect dependencies.
- What you can do after
- Diagnose transitive dependencies and redesign affected tables with separate entities and foreign-key links.
Read how Grokking Relational Database Design explains transitive dependency →
Related concepts
- dependencykind of · A software dependency is a component, resource, or prerequisite on which another software component or operation relies to function or proceed.
- Go compilercontrasts with · The Go compiler is the program that checks Go source code and translates it into executable machine code or an intermediate representation.
- third normal formcontrasts with · Third normal form is a relational schema condition in which the relation is in second normal form and non-key attributes depend only on the key, not transitively on other non-key attributes.
- normalizationaddresses · Normalization is the process of transforming a value, representation, or data structure to satisfy a specified standard, scale, or structural constraint.
- denormalizationproduced by · Denormalization is the deliberate combination or duplication of related data to simplify access, support particular access patterns, or improve performance.
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