| 摘要 |
Methods, systems, and computer program products for converting a single expression referencing multiple branches within a hierarchical schema into multiple expressions referencing a single branch of the hierarchical schema. The single expression includes expression components that identify branches within the hierarchical schema. Relative to a given branch, any branches referenced by a given expression component are identified. The identified branches are stored as new branches. If no branch is identified, the current branch may be removed as inconsistent. Storage for current branches is cleared, the new branches are copied to the current branches, and the process is repeated for each expression component. An expression component may include a predicate for determining which branches are referenced. The predicate may include predicate expressions that are converted to predicate branches and the predicate may include predicate operators. Predicate operators are combined with predicate branches to identify all branches referenced by the predicate.
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