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Most composite views should to gather all the required data from the table views for the same snapshot as illustrated in
| Caption reference |
|---|
| CapRefId | source-views-for-data-in-composite-views-of-different-snapshots |
|---|
| CapRefType | Table |
|---|
|
.
| Caption label |
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| CapId | source-views-for-data-in-composite-views-of-different-snapshots |
|---|
| CapType | Table |
|---|
|
Source Views for Data in Composite Views of Different Snapshots |
| Composite View | snap_pref
| snap1_pref
| snap2_pref
|
| Description View | snap_description | snap1_description | snap2_description |
| Language Refset View | snap_refset_language | snap1_refset_language | snap2_refset_language |
Composite views may themselves gather data from other composite views. For example as shown in gets in
| Caption reference |
|---|
| CapRefId | composite-view-including-data-from-another-composite-view |
|---|
| CapRefType | Table |
|---|
|
gets preferred term data from the preferred term composite views shown above.
| Caption label |
|---|
| CapId | composite-view-including-data-from-another-composite-view |
|---|
| CapType | Table |
|---|
|
Composite View Including Data from Another Composite View |
| Composite View | snap_rel_pref | snap1_rel_pref | snap2_rel_pref |
| Concept View | snap_concept | snap1_concept | snap2_concept |
| Relationship View | snap_relationship | snap1_relationship | snap2_relationship |
| snap_pref | snap1_pref | snap2_pref |
Composite views designed to support review of changes may gather data from different views as illustrated in
| Caption reference |
|---|
| CapRefId | source-views-for-data-in-historical-composite-views-of-different-delta-views |
|---|
| CapRefType | Table |
|---|
|
.
| Caption label |
|---|
| CapId | source-views-for-data-in-historical-composite-views-of-different-delta-views |
|---|
| CapType | Table |
|---|
|
Source Views for Data in Historical Composite Views of Different Delta Views |
| Composite View | delta_inactive_concepts
| delta1_inactive_concepts
| delta2_inactive_concepts
|
| Concept View | delta_concept | delta1_concept | delta2_concept |
| Association Refset View | snap_refset_association | snap_refset_association | snap_refset_association |
| Attribute Value Refset View | snap_refset_attributevalue | snap_refset_attributevalue | snap_refset_attributevalue |
| snap_pref | snap_pref | snap_pref |
Fully Specified Name View | Footnote Macro |
|---|
The views snap_fsn, snap1_fsn and snap2_fsn are composite views similar to snap_pref but return the fully specified name rather than the preferred term. |
| snap_fsn | snap_fsn | snap_fsn |
Representation of Composite Views
Composite views should be represented as database views rather than a physical database tables. Composite views denormalize data by combining the same data in different views therefore attempts to represent composite views as database tables is likely to rapidly multiply the size of the database. The example below is just one of many cases where creating concrete database tables to accommodate composite views might seem an attractive idea. However, pursuing this would create redundant data with few benefits, a major impact on storage requirements and a significantly more complex maintenance process when reviewing and installing future release packages. In contrast, representing composite views as database views, ensures the data is derived in real-time from tables representing the authoritative content of the full and/or snapshot release files.
| Info |
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Most english English language descriptions are either preferred or acceptable in both US and GB english. Therefore instantiating tables that represent the sets of preferred and acceptable terms in either or both dialects would not only duplicate much of the data in that table but would require even more space to duplicate the relevant indexes. In addition to the impact of disk space, data duplicated in these composite tables would need updating to take account of new releases. |
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