Tuple A tuple is a partial function from attribute names to atomic values. Header A header is a finite set of attribute names. Projection The projection of a tuple t on a finite set of attributes A is .
Coordinate Tuple
A coordinate pair or triplet. (See also Tuple)
Coordinates ...
coordinates A tuple of ordered scalar values that define the position of a single point feature in a coordinate reference system. The tuple is composed of one, two or three 'ordinates'.
In SQL terms, a record is analogous to a tuple.
2. A logical unit of data in a file. For example, there is one record in the ARC file for each arc in a coverage.
Constraint databases generalize the classical relational model of data by introducing generalized tuples: quantifier-free formulas in an appropriate constraint theory.
The basic data structure of the relational model is the table, where information about a particular entity (say, an employee) is represented in columns and rows (also called tuples).
These are ordered tuples of real values that represent fields of directions.
record
1. In an attribute table, a single 'row' of thematic descriptors. In SQL terms, a record is analogous to a tuple.
2. A logical unit of data in a file. For example, there is one record in the ARC file for each arc in a coverage.
of attribute values pertaining to a geographic object. In a Flat file or a Relational table, records make up the rows; and individual attributes make up the columns. In relational database terminology, a record s formally called a tuple.
 See also: Information, Object, Model, Database, Relation
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