Terminology - Database Design for Mere Mortals - page 40

Figure 3.9. A table containing regular, calculated, multipart, and multivalued fields
I'll cover calculated, multipart, and multivalued fields in greater detail in Chapter 7 , “ Es-
tablishing Table Structures .”
Record
A record (known as a tuple in relational database theory) represents a unique instance of
the subject of a table. It is composed of the entire set of fields in a table, regardless of
whether the fields contain values.
Because of the manner in which a table is defined, each record is identified throughout the
database by a unique value in the primary key field of that record.
In Figure 3.9 , each record represents a unique client within the table, and the C LIENT ID
field will identify a given client throughout the database. In turn, each record includes all
of the fields within the table, and each field describes some aspect of the client represented
by the record. Consider the record for Timothy Ennis, for example. His record represents a
unique instance of the table's subject (“Clients”) and includes the total collection of fields
in the table, treated as a unit. The values of those fields represent relevant facts about Mr.
Ennis that are important to someone in the organization.
Records are a key factor in understanding table relationships because you'll need to know
how a record in one table relates to other records in another table.
View
A view is a “virtual” table composed of fields from one or more tables in the database; the
tables that comprise the view are known as base tables . The relational model refers to a
view as being “virtual” because it draws data from base tables rather than storing data on