[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: XInclude [was: XLink transformations]
Sorry to be tedious, Paul. I want to be sure I understand the different abstractions so I can present them correctly. I understand your answer. In a relational system, data in a view can be appended to the recordset (table) thus creating new records versus say an update in which new values are written into preexisting records. The SQL is an Insert Into. So INSERT INTO target [(field1, field2 VALUES (value1, value2) vs UPDATE table SET newvalue WHERE criteria Simply, INSERT creates new records and UPDATE overwrites existing records. In the table, order of records is not a guaranteed abstract property as a means to identify a record (identity is invariant to transform by insertion). While the operations of first, last, previous and next (navigating recordsets) is enabled, only by comparing a value can one determine the identity of the record. Thus, recordset walking is often an expensive but unavoidable operation and the implementor writes a routine using the Previous/Next/Last/First methods to get and set values. XInclude is operationally an Insert Into except that there is also the concept of the abstract property of position in the target; that is, the inclusion or insert occurs at the position of the XInclude statement. Order is preserved. Positions of information items following the inclusions increment. In the relational system, this is unimportant. In the tree, it can be. When comparing these systems, it is important for the implementor to understand the properties of position and order in the abstract information set and how the XInclude operation affects it. This can determine on which side of mixed systems certain operations are best performed. Len Bullard Intergraph Public Safety clbullar@i... http://fly.hiwaay.net/~cbullard/lensongs.ram Ekam sat.h, Vipraah bahudhaa vadanti. Daamyata. Datta. Dayadhvam.h -----Original Message----- From: Paul Grosso [mailto:pgrosso@a...] ...I think the answer is that you are not mistaken; XInclude preserves order. As I said earlier: "All information in the included bit is included at the including point" paul
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