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Relational Database Model

Stores information in related tables using keys. Data Table

Data Subset Table

Stores extra info for a subset of a Data Table.

Linking Table

Connects two tables in a many-to-many relationship. Validation Table

Functional Dependencies

Functional Dependency

One attribute determines another. Determinant

Decomposition

If A→B,C then A→B and A→C.

Composition

If A→B and A→C, then A→B,C.

Multivalued Dependency

One attribute determines multiple independent values. Full Functional Dependency

Keys

Superkey

Attributes that uniquely identify each row.

Candidate Key

Minimal Superkey; uniquely identifies rows.

Primary Key

Chosen Candidate Key; not null.

Alternative Key

Candidate Key not chosen as primary.

Non-Key Field

Column not part of any key.

Foreign Key

References a key in another table.

Composite Key

Two or more columns act as one key.

Surrogate Key

Artificial unique ID with no real meaning. Auto-Incrementing

Integrity

Referential Integrity

Foreign key must match existing primary key. Data Integrity

Validity

Data follows correct format and allowed values.

Consistency

Data does not contradict other data. Accuracy

Fields & Normalization

Tuple

A row in a table.

Multipart Field

Single column storing multiple pieces of info.

Duplicate Fields

Multiple columns storing similar info.

Multivalued Field

One column stores multiple values.

Calculated Field

Derived from other columns.

Anomaly

Data error from insert/update/delete issues.

Normalization

Restructuring to reduce redundancy and improve integrity. Relation

Normal Form

Set of rules defining normalization stages.