Changes between Version 7 and Version 8 of S3/S3Model/SuperEntities


Ignore:
Timestamp:
11/01/10 23:43:31 (11 years ago)
Author:
Dominic König
Comment:

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  • S3/S3Model/SuperEntities

    v7 v8  
    1313The primary resource (=instance table) contains the same ''super-key'' field as the component, thus the forward join of resource-to-component can be established as a natural join, i.e. without accessing the link table.
    1414
    15 For the (seldom needed) backward join component-to-resource, the link table needs to be involved because it contains the table name of the primary resource in the field {{instance_type}}.
     15For the (seldom needed) backward join component-to-resource, the link table must be involved because it contains the table name of the primary resource in the field {{instance_type}}.
    1616
    17 Disadvantage of the link table method is that the link table needs to be updated whenever a primary resource record is created, updated or deleted - which generates some (minimal) extra load on write, however, it is recommended to not use super-entities for resources where the extra load on write can give a serious performance problem (e.g. messages), or at least to keep the super-entity table lean and free of extra references.
     17Disadvantage of the link table method is that the link table has to be updated whenever a primary resource record is created, updated or deleted - which generates some (minimal) extra load on write, however, it is recommended to not use super-entities for resources where the extra load on write can give a serious performance problem (e.g. messages), or at least to keep the super-entity table lean and free of extra references.
    1818
    1919  - ''code examples to follow...''