Shared tables normally points to a table in which there are two foreign key constraints (to two other primary tables). In Versioned Repository, you cannot share a multi table with more than 2 tables. Its because, one of the foreign key should use the asset version and the other one will use the secondary asset version (shared-table-sequence=2)
Table A - Primary
Table B - Multi
Table C - Primary
B will have 5 columns here.
C1 - A's ID
C2 - A's Asset Version
C3 - Seq Number
C4 - C's ID
C5 - C's Asset Version (Secondary Asset Version)
Secondary Asset Version column will be owned by the table which has shared-table-sequence as 2.
Hope this helps.
shared-table-sequence is specifically used for version repositories between tables which share a relationship. It tells the relationship between 2 tables. By default, if it is a simple one to one or one to many, even if we don't specify it explicitly, it takes the shared-table-sequence as 1. In a two sided one to many or many to many relationship, like the example above, it is used to determine the tables that corresponds to the asset_version(shared-table-sequence=1) and sec_asset_version(shared-table-sequence=2) columns.
The sequence number (seq_nbr) which we normally use for a list is different. This is present in all multi table for making one to many relationships possible. This will part of the multi table's composite key.