Design Database Hierarchy

All Marine data is stored in a hierarchic or ‘tree’ format in the case of a Design database, the topmost data level is called the World (usually represented by the symbolic name /*), below which are the administrative sub levels Site and Zone.

The names used to identify database levels below Zone depend on the specific engineering discipline for which the data is used. In the case of ASL design data, the lower administrative levels (and their Marine abbreviations) are Structure (STRU) and Substructure (SUBS).

All data is represented in the database thus:

• Each identifiable item of data is known as a Marine element.

• Each element has a number of associated pieces of information, which, together, completely define its properties. These are known as its attributes.

Every element is identified within the database structure by an automatically allocated reference number and, optionally, by a user specified name. Additional items of information about an element which could be stored as attribute settings include:

• Its type

• Its physical dimensions and technical specifications

• Its physical location and orientation in the design model

• Its connectivity.

Some attribute settings must be defined by the user when creating a new element, others will be defined automatically by Marine.

The vertical link between two elements on adjacent levels of the database hierarchy is defined as an owner-member relationship. The element on the upper level is the owner of those elements directly linked below it. The lower level elements are members of their owning element. Each element can have many members, but it can have only one owner.

When modifying a database (for example, when creating new elements or changing the settings of their attributes), consider yourself to be positioned at a specific point within the hierarchy. The element at this location is called the current element (often abbreviated to CE).

The user can navigate from any element to any other, thereby changing the current element, by following the owner-member links up and down the hierarchy.

In many cases, commands given by the user for modifying the attributes of an element assume that the changes are to be applied to the current element unless specified otherwise, so the user must understand this concept and always be aware of the current position in the database hierarchy. The Design Explorer displays this information.