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Before you can edit an entity there are some criteria that need to be met, firstly the entity id must be unique within a spatial table.
If an entity is composed of multiple spatial tables then it may be the case that the id may not be unique across all of the tables, if for example the entity is composed of more than one geometry type and the underlying spatial engine (e.g. ArcSDE, shapefiles) doesn't support different geometries in a single table, then the geometry would need to be spread over more than one table. In this situation the entity id would have to be the same in all of the spatial tables, but it must at least be unique within each table, this is the only way that Weave can determine which row in the table that it needs to update (it determines which spatial table to update based on the geometry type stored in the spatial table).
Multiple For editing multiple spatial tables are only fully supported when a different geometry types are type is stored in each table. That is if an entity is linked to more than one spatial table then each spatial table should contain a different geometry type (point, line or polygon), this is so that Weave knows which table to write the appropriate geometries to, for example if you were to have an entity linked to two spatial tables, both containing polygon geometry, then when an edit was submitted than contains a polygon Weave would not know which table the geometry was supposed to be added to or updated in.
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Additionally, at this stage spatial engines that don't differentiate between geometry types, i.e. the spatial table stores "geometry" and not specifically points, lines or polygons, are not currently support in multi table configurations, since Weave can not determine which table to write the geometry to (they are supported in single table configurations). This may change in the future.
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