Importer Manual / Version 2101
Table Of ContentsSince the term "document" is inevitably used rather often in this manual, it is important for understanding this chapter to distinguish between the following types of documents:
Source document: a document of any format for import, for example a file or a generated DOM tree. This term includes both the input data and the intermediate results of the transformers.
XML document: a document of any XML format, for example CoreMedia XML.
CoreMedia document: a document in the sense of the CoreMedia CMS. For example, a <document> in the CoreMedia XML format represents a CoreMedia document.
There is no one-to-one relationship between source documents and CoreMedia documents. As you can see from the example of CoreMedia XML above, a source document can represent several CoreMedia documents. On the other hand, a transformer can generate a single CoreMedia document from the contents of several source documents.
Due to the requirements for consistency over documents (especially the referential integrity), in many cases it is not possible to import individual CoreMedia documents. Often, a group of CoreMedia documents which can only be imported together results from many source documents. The importer therefore offers the possibility of processing any number of source documents in one operation.
On the other hand, a large number of source documents significantly increases both the amount of memory required and the time required for consistency testing. Many operations with fewer documents are more efficient than fewer operations with many documents. Therefore, ideally, the source documents should be imported individually and then be combined into the smallest possible groups, if required by the referential integrity.
