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To avoid any confusion and misinterpretation it is important that the input data is represented in a way that ease the interpretation of the input data and ensure correct processing of the expression template. Poorly represented input data may result in expressions that express a different meaning than intended, which can be critical if the resulting expressions are used for safety critical purposes (storage, communication, trigger decision support rules etc.)
Templates with Repeatability of Groups and Attributes
In situations where the template allow for attribute-value pairs or relationships groups to be repeated, the input data should be explicit about
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@Expression | @Group | @Site | @Morphology | ||||||||
1 | 1 |
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2 |
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2 | 1 |
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3 | 1 |
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4 | 1 |
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The above input data would result in following four expressions to be generated when processing the template:
| Expression | |||
|---|---|---|---|
| 1 |
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| 2 |
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| 3 |
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| 4 |
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Templates with Cardinality Constraints
Specifying the expression and group when representing input data is particularly important when the template includes cardinality constraints, to be able to determine the repeatability of groups and attributes. Expression templates which specifies a [1..1] cardinality of slots or expression parts can omit the group column, as shown in the following example.
Cardinality Constraints on Groups
Consider the following template, where the template includes a cardinality constraint on the group like this:
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| @Expression | @Group | @Site | @Morphology | Processing Result | ||||||||
| 1 | 1 |
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| INVALID Only one group is allowed due to cardinality constraints | ||||||||
2 |
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| 2
| 1 |
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| VALID | ||||||||
1 |
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| 3 | 1 |
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| VALID | ||||||||
| 4 | 1 |
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| VALID |
So in this case, there would be no need to include the second column in the input data to differentiate between different groups in the same expression. Hence, the input data could be simplified as:
| @Expression | @Site | @Morphology | ||||||||
| 2
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| 3 |
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| 4 |
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Cardinality Constraints on Attributes
Consider the following template, where the template includes a cardinality constraint on each attribute like this:
| Scg expression | ||
|---|---|---|
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[[@Expression ]] 64572001 |Disease| : [[1..*]]
[[1..1 @Group]]{ [1..1] 363698007 |Finding site| = [[+ (<< 272673000 |Bone structure| ) @Site]],
[1..1] 116676008 |Associated morphology| = [[+ (<< 72704001 |Fracture| ) @Morphology]] } |
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@Site | @Morphology | ||||||||
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Summary
In summary, it is recommended to be as explicit as possible when specifying input data for expression templates. However, in situations the input data can be simplified, and then following default can be assumed by the input data:
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