Re: [sdo] SDO-148: Specify ChangeSummary serialization format forarrays

Hi everyone,

I won’t be able to attend today’s meeting. But I worked on SDO-148 this week (“Specify ChangeSummary serialization format for arrays and Sequences”). I’ve some questions and an early proposal I’d like to share with you.

1. The sdo:ref attribute accepts both IDREFs and XPath values. But are IDREFs acceptable for sdo:range as value? We believe sdo:range should only have XPath values.

2. Are sdo:range and sdo:ref mutually exclusive? If the XML format has both attribute on the same element, how an implementation should behave? We thought of 2 possibilities:

a. Ignore the sdo:ref declaration. In that case only the value in sdo:range is interpreted, sdo:ref value is ignored.

b. Throw an exception to the SDO user indicating that the XML format isn’t correct.

3. Should we allow/support sdo:ranges on all XML change summary elements? In this example the following XML fragment summarizes 4 departments that share the same employees:

</departments>

</changeSummary>

In this case an SDO implementation would have to ensure all elements reachable from a “department” remain the same. We think this as a potential performance issue for an implementation. We would then propose that an implementation should support deserialization but isn’t required to produce this format.

Here are the changes I propose to the specification:

Add a paragraph to the core spec, section 10.2 after first paragraph.

When serializing list of consecutive references to DataObjects as a value of an sdo:range attribute an SDO implementation MUST use IDREFs when IDs are available, and XPath expressions otherwise (See question 1) [COR1002xxxx]. The sdo:range attribute value MUST contain a reference to the range start and a reference to the range end separated with a white space character. [COR1002xxxx]. The following examples are equivalent:

</departments>

</changeSummary>

</departments>

</changeSummary>

Add the sdo:range (here in bold) attribute in second paragraph of section 10.2

XPath expressions are distinguishable from ID references in that they start with a „#‟ character. Key properties, other than those identified using the schema ID type, are not used as values of sdo:ref, sdo:range, or as elements of the created or deleted lists.

Add a sentence (here in bold) in first paragraph in section 10.4

If the property's type is not a dataType, an SDO implementation MUST render unaltered elements using the sdo:ref attribute to indicate the corresponding object in the final document or the sdo:range attribute to indicate a range of corresponding objects in the final document. [COR10040003]

Thanks,

François Huaulmé

O. +33 (0)1 46 14 13 08 | E. francois.huaulme@datadirect.com | F. +33 (0) 1 46 14 13 01

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