alias ~ Collection.
idea ~ Combine a number of elements to a larger structure.
context ~ A set of multiple data elements.
motivation ~ Combine multiple independent elements on the same level to refer to them as a joint group.
implementations ~ - Explicitly list all member elements which belong to the container. - Specify a method to check whether an element belongs to the container.
examples ~ - A directory of files in a file system. - An archive containing a set of files. - A set of records in a database. - A repeatable entity or relationship in a schema. In fact the concept of repeatability is an instance of the container pattern. - An entity type in a schema is the set of all of its instances.
counter examples ~ A single record with its properties does not constitute a container because properties depend on the record instead of being independent.
difficulties ~ - A container may hold a single member element only, making the collection difficult to distinguish from the element as such. - A container may be empty, making it difficult to list member elements.
related patterns ~ - Explicitly listing member elements requires a sequence. - A membership function is a form of derivation. - Empty containers often involve an implicit element (void). - Collections are used to refer to elements (or to a type of elements) with a human readable label. - Each collection defines the property of "belonging to the collection". An alternative pattern to group by same properties is normalization. - Collections may be abbreviated (etcetera pattern). - Containers are also used to wrap or abstract from sets of data. This goal can better be achieved by atomicity.
implied patterns ~ - A container is a special kind of embedding with member elements embedded into the collection as host element. - Unless abbreviated, containers have a specific number of member elements which implies the size pattern.
specialized patterns ~ A sequence and a graph typically consist of collections of elements.