Master the visual language of database modeling. Understand relationships, constraints, and optimization strategies.
1NF: Atomic values. 2NF: No partial dependencies. 3NF: No transitive dependencies.
Inner (Match), Left (All Left + Match), Right (All Right + Match), Full (Everything).
Clustered (Physical Sort) vs Non-Clustered (Logical Pointer). B-Tree is default.
Unique identifier for a row. Cannot be NULL. Ensures entity integrity.
A field that links to the Primary Key of another table. Enforces referential integrity.
A Primary Key made of multiple columns. Used in junction tables (M:N relationships).
Adding redundancy (e.g., storing 'count' on parent) to avoid expensive joins on reads.
A row in Table A links to multiple rows in Table B (e.g., User -> Orders).