I think a foreign key restraint is basically a trigger that throws an
exception (RAISE statement) when the restraint is violated.
Something trigger function like:
If table1
if not in table1
raise
else if table2
if not in table2
raise
end
I think that should work, but I've never tried it.
MargaretGillon@xxxxxxxxxxxxxx wrote:
Postgresql 8.1.4 on Redhat 9
I have a table which stores M:M relationships. I can't put foreign
keys to the parents of this table because the relationships being
stored go to several tables. This was done so that only two fields
have to be searched in order for all relationships to be found for an
item. For an oem number there might be 50 to 100 relationships and 40
different tables having to do with materials, locations, revisions,
specifications, customer, etc. that might be referenced.
Is there some way I can make a mock foreign key restraint on the
parents so the parent would search the M:M table for a matching value
in key1 if the relate-key is 22, 23, 25 or 100 before it allows the
row to be deleted?
relate-key relate-type key1 table1
key2 table2
22 product-material 23 oem 545
material
22 product-material 23 oem 546
material
23 product-engine 23 oem
15 engine
25 product-stage 23 oem 3
stage
100 product-revision 23 oem 2270
specifications
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Margaret Gillon, IS Dept., Chromalloy Los Angeles
