Relations establish links between objects. These links define the structure of a publication. Three types of relationships are available:
• Association: A simple connection between objects. No object is dependant on another. There is no parent/child relationship. For example, a TorP notice in a previous publication is now a cancelled notice in a new chart notice.
• Aggregation: A relationship to a collection of objects. Objects in a collection may also be included in other aggregations. This allows an object to be shared. For example, a chart notice section can contain multiple chart or TorP notices.
• Composition: The parent or source object is composed of children or target objects. The objects in the composition are not shared with other objects. If the parent object is deleted the children objects are also deleted.
Relations between objects is shown in the following image.
From the above image, the following relations are established between objects:
• “Notice to mariner section” relation creates a link between the parent or source (NTC_PUBLICATION) and the target or child (NTC_SECTION_CHART) objects. This is a composition relationship – if NTC_PUBLICATION is removed then the NTC_SECTION_CHART is also removed.
• “Chart notice section” relation creates a link between the source (NTC_SECTION_CHART) and targets (NTC_CHART and NTC_TORP). This is an aggregation relationship which means that the source is linked to a number of targets. If one target is removed, the other targets are still active. For example, the removal of NTC_TORP does not affect either NTC_CHART or NTC_SECTION_CHART.
• “Chart notice instruction” relation is a composition relationship. If either parent object is removed, the instructions are also removed.
• “Cancelled notice” relation creates an association link between a temporary or preliminary notice from a published publication and the target (NTC_CHART) in the current publication.
Some objects must be set with mandatory relations if the application is to successfully link objects. All the relations must be added exactly – this includes spelling and upper-case characters. These relations are described in the table below:
Relation | Description |
|---|---|
SECTION | A Composition relation defining the ownership of a Section. A Publication is expected to have sections and Sections can be defined to have sub-sections (SECTION Compositions between a Section and other Sections) |
SECTION_CONTENT | A Composition or Aggregation relation between a Section object and its contents/records. For example Chart Notice Section would have an aggregation of Chart Notices, such that a notice could be shared or included in another publication. A Light List Section would be a composition of light records. |
INSTRUCTION | A Composition relation used to define which Instructions can be used for a given Notice type. A Notice can be comprised of different types of Instructions. |
CANCELLED_NOTICE | Association relation for a cancelled notice. The source of the cancelled notice is the Notice that is cancelling the Target Notice. For example a Chart Notice can cancel a Temporary Notice. The relation can be defined with multiple sources and targets meaning that multiple Notice types can cancel one or more Target types. You can even allow the same type for both source and target for example to define that a Temporary Notice can cancel another Temporary Notice. |
LIST_RECORD | An Association relation used by the system to relate a list record notice instruction to a List record. Used/populated when the Generate List Record Notices command is run. |
An example of how these relations are applied in publication_catalogue.xml is shown below. The relations are grouped by publication component.
Relation | Description |
|---|---|
Catalogue Notice | |
SECTION_CONTENT | Aggregation relation between a catalogue notice section (source) and the catalogue notice (target). |
INSTRUCTION | Composite relation between a catalogue notice (source) and a catalogue notice instruction (target). |
Chart Notice | |
SECTION_CONTENT | Aggregation relation between a chart notice section (source) and the following targets: • Chart notice • Temporary or preliminary notice |
INSTRUCTION | Composite relation between a chart notice (source) and a chart notice instruction (target). |
CANCELLED_NOTICE | Association relation for a cancelled notice. The source of the cancelled notice is either a chart notice or a temporary or preliminary notice (source). The target is a temporary or preliminary notice (target) |
General Notice | |
SECTION_CONTENT | Aggregation relation between a general notice section (source) and a general notice (target) |
INSTRUCTION | Composite relation between a general notice (source) and general notice instruction (target). |
Light Notice | |
SECTION_CONTENT | Aggregation relation between a light notice section (source) and a light notice (target). |
INSTRUCTION | Composite relation between a light notice (source) and a light notice instruction (target). |
Radio Services Notice | |
SECTION_CONTENT | Aggregation relation between a radio services notice section (source) and a radio services notice (target). |
INSTRUCTION | Composite relation between a radio services notice (source) and a radio services notice instruction (target). |
Sailing Direction Notice | |
SECTION_CONTENT | Aggregation relation between a sailing direction notice section (source) and sailing direction notice (target). |
INSTRUCTION | Composite relation between a sailing direction notice (source) and a sailing direction notice instruction (target). |
Temporary or Preliminary Notices | |
SECTION_CONTENT | Aggregation relation between a chart notice section (source) and the following targets: • chart notice • temporary or preliminary notice |
INSTRUCTION | Composite relation between a temporary or preliminary notice (source) and a chart notice instruction (target). |
Notice Publication | |
SECTION | Composite relation between a notice group or notice publication (sources) and the following targets: • Catalogue notice section • Chart notice section • General notice section • Light notice section • Notice group • Radio services notice section • Sailing direction notice section |
Light List Publication | |
SECTION | Composite relation between a list product publication or list group (sources) and any of the following targets: • Light list record section • List group |
SECTION_CONTENT | Composite relation between a light record section (source) and a light record (target). |