# Table Linkage
Monkey patching: add another column. No new IDs. A unique thing.

Table A is linked to table B. It should probably be called "dependence", but the word's got too many e's.
This is fairly complex. We're attempting to define a notation for this.

Hard symmetric ≤=≥: Removing a row from one table removes it from the other.
Soft symmetric <=>: Removing a row from one table nulls out the corresponding field in the other.
Hard

## Hardness
hard: suicide pact
soft: parasitic
weak: persists

hard linkage:
    Removing a row (or rows) from either table removes the corresponding row(s) from the other.

soft linkage:
    Removing the foreign row removes the local row. Removing the local row does nothing to the foreign row.

weak linkage:
    Removing the foreign row nulls out the local row.

## Count
{1, [0-1], 1+, 0+}×{1, [0-1], 1+, 0+}
1?+*
    one maybe many any