Schema Diagrams




A database schema, along with primary key and foreign key dependencies, can be depicted by schema diagrams. Figure 2.8 shows the schema diagram for our university organization. Each relation appears as a box, with the relation name at the top in blue, and the attributes listed inside the box. Primary key attributes are shown underlined. Foreign key dependencies appear as arrows from the foreign key attributes of the referencing relation to the primary key of the referenced relation.

Schema Diagrams

 

Referential integrity constraints other than foreign key constraints are not shown explicitly in schema diagrams. Entity relationship diagrams let us represent several kinds of constraints, including general referential integrity constraints.Many database systems provide design tools with a graphical user interface for creating schema diagrams. 

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Frequently Asked Questions

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