composite key

This happens when there is more than one unique composite key and they overlap.

Therefore the primary key for this entity is a composite key.

A primary key may be a composite key.

Keys can comprise several columns, in which case they are composite keys.

In fact, use of a composite key such as this can be a form of data verification, albeit a weak one.

A composite key is a key made up of two or more attributes within a table that (together) uniquely identify a record.

The fact table contains relevant measures and a composite key defining what these measures describe.

A composite key is necessary because no single attribute will uniquely identify a tuple of this relation.

A composite key contains at least one compound key and one more attribute.

Another common occurrence, especially in regard to N:M cardinality is the composite key.

Recognize when to use composite keys.

Alteratively the composite key 'election year' and a new attribute 'election number in year'will be adequate.

The primary key of a fact table is usually a composite key that is made up of all of its foreign keys.

Composite keys, unlike compound keys may also include simple keys and non-key attributes.

The problem comes about because all three attributes form the composite key: there are no functional determinants apart from this combination of all three attributes.

Direct engine-level access via simple or composite keys can store and retrieve, in one access operation, variable-length records with variable-length values.

Classes could be uniquely identified by a composite key of their room number and time slot, since no other class could have exactly the same combination of attributes.

It is best if a primary key is a single attribute, but it is possible to have a composite key comprised of more than one attribute.

The key of the relation of Figure 3.24(b) is 'course-number' and 'module-number'together (a composite key) and the key attributes have been underlined.

A COMPOSITE KEY is simply a key that contains more than one attribute.

A column that appears in both boldface and italics is a primary key (or part of a composite key) in one table and a foreign key in another.

This evaluation was possible for the 60% of individuals who had a social insurance number (SIN) either supplied or found through the use of a composite key generated as part of the work process.

The PostgreSQL GiST implementation includes support for variable length keys, composite keys, concurrency control and recovery; these features are inherited by all GiST extensions.

For example, the following two relations in Figure 4.18, COURSE and SUBJECT, both have course as the key, but the latter has it as only part of the composite key with subject.

The basic engine provides multi-valued or set attributes, all primitive Java types, unlimited large objects, heterogenous values, composite keys (Entities) and values, and unlimited sparse attributes, all extensible in-place with no schema changes.