Management of complex XML schemas in a database system

摘要

Techniques manage the presence of repeated constructs within a complex type at the time of schema registration. At registration, techniques detect repeated elements in the XML schema and analyze whether the repeated elements are from the same complex type. If so, techniques perform additional analysis to determine a minimal common ancestor. Within the context of a minimal common ancestor, techniques determine the maximum number of times an element may occur in the schema. In a choice content model, the largest maximum occurrence value is selected. In other content models, the maximum occurrence value is determined by adding together the occurrence values for the repeated elements. Then, when an object relational table is generated for the XML schema, the maximum number of times that an element appears in the schema is this value. Techniques retain the advantages of object relational storage, even after a schema evolution.