In a relational database approach, regardless of whether one is considering persisted data or transitory query results, almost everything is viewed as a logical table. Associations between these ...

A foreign key is a relationship between two entities. Generally speaking, inter-entity relationships are one-to-many, e.g., an ORDER has many ORDER LINEs, and so forth. Even a case that may start out ...

I'm adding a table and subclass table to my DB. (Subclass table = table where the primary key joins to the primary key of another table, to give extra row information to some subset of the rows.

Databases are used in many different settings, for different purposes. For example, libraries use databases to keep track of which books are available and which are out on loan. Schools may use ...