For some products, a variety of changes in demand, variability good design is very important. Siebel has done well abroad, domestic Kingdee BOS, Kingdee BOS actually a lot of ideas with Siebel are similar, huh, huh. . . They are based on MDD way to solve the problem of variability.
The difficulty here is how to abstract a stable element model can describe a wide variety of changes, you can get in order to achieve the purpose by the configuration requirements change.
Here to talk about the focus on meta-model Kingdee BOS so-called meta-model, it is a model of the model.
In the data layer, there Table, the Table correspond to the database table, a direct relationship between the three kinds Table, what cross-table and the extension table and the like, substantially corresponding to all the usual paradigm design table, not more than that;
Yewuluojiceng, entities, physical entities represent objects art system, an entity corresponds to a Table, the attributes of the entity corresponding to the field or extensions Field Table table, a relationship between entities and entities, relationships into One2One , One2Many, Many2One, Many2Many. You may also be defined for the entity attribute calculation formula constraint. But the lack of entity-level constraints. I think that Kingdee can increase the characteristic small :). Inheritable entity from another entity, another entity in order to obtain defined.
It can be mapped to a rule entity definition process, process. That call this method when the actual implementation of this rule is;
Entity can define a query program, filtering program, ordering scheme, mainly way to do OO query entity, foreign exposure OO-oriented user interface, internally generated SQL with;
It can be defined as an entity event, Function and Facade can listen to events, events triggered by Function.
Function explanation is kingdee "Entity objects are business function of operation of the system, and some UI objects encapsulation method, or for other modules developed using secondary," such as the above-mentioned events, i.e. triggered by Function producers, but I do not know why the method specified event, Function event, the method of representation of the event consumer event (listener), so do not lead to producers and consumers coupling yet? ? That event also do not know if I have a friend can answer this question? ? Function Action can also be bound to a UI, which means when the UI object Action trigger, will perform this Function. Binding of UI Action is optional.
Facade Service field representing an object, compared to the entity, which only have a method, no attribute.
UI object represents an interface object, such as order to create an object, it can specify Layout, UI object supports binding entity, Query object. UI objects also have events, Action and status, events, and Action should be bound to the Function and Facade, State represents the state of the interface objects, such as interface usually edit mode, view the status and so on. UI objects there is a parent, not how to figure out the relationship between the object and the UI UI objects, do not see a description of the need for further research; feeling BOS UI abstraction layer bit simple, usually the UI layer is the most complex with field linkage, the linkage sub-pages and so on, did not see how to get this linkage BOS scene.
Represents a query for a query object, you need to bind an object tree, define a query, the filtration scheme, ordering scheme used to generate SQL;
There are some other non-primary element model.
By UI Object, Entity / Function / Facade , and Table, the interface can support the description, domain objects / services, database tables binding relationship between them and, if the object model has changed, or there is a change business logic, it can lead to three the change in the object layer, and may vary based on the meta-model describes the three layers, the configuration can be achieved by.
----------------
Disclaimer: This article is CSDN blogger "liaoxingya276 'original article, follow the CC 4.0 BY-SA copyright agreement, reproduced, please attach the original source link and this statement. .
Original link: https: //blog.csdn.net/liaoxingya276/article/details/7342656