377 ;;Quote: data description does not support collections of data; hard to change without impacting applications

377+;;Quote: avoid representational dependencies in data; e.g., ordering, indexing, and access path

379 ;;Quote: a relation is a subset of the Cartesian product of a set of domains; i.e., n-tuples of elements from each domain

380 ;;Quote: a primary key is one or more domains that uniquely identifies tuples of a relation

380 ;;Quote: a foreign key consists of values for the primary key of a relation

380 ;;Quote: relational model treats entities and relations the same; unlike earlier models

380+;;Quote: foreign keys blur the distinction between entities and relations

381 ;;Quote: store simple domains as tables with homogeneous columns

381+;;Quote: use normalization to remove nonsimple domains

382 ;;Quote: query a relation using any combination of arguments as knowns and unknowns; an advantage of relational databases

382 ;;Quote: the named set of a relational database is a very small subset of the expressible set of relations

382 ;;Quote: need efficient translation from a high level data language to the stored representation; necessary for concurrent access to a large data bank

383 ;;Quote: a projection is a relation without certain columns and without duplicates

383 ;;Quote: a natural join is the result of combining two relations using a shared domain