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Integrity Constraint Violation
From NeoWiki
Integrity Constraint Violation
- Explanation
The full text will be something like this:
Integrity constraint violation - no parent 4, table: Table A in statement [ALTER TABLE "Table A" ADD FOREIGN KEY ("field name A") REFERENCES "Table B" ("field name B")
It occurs when you are trying to relate Table A to Table B by means of the two fields named. The field from table A ("field name A") is called a Foreign Key (FK). Any field that links into another table (Table B, in this case) is called a Foreign Key. Remember that every table must have its own Primary Key (PK)
It means that there is data in field name A on one of the records in Table A that does not match any of the data in field name B on the records in Table B.
- Solution
Check your data. Make certain that every record in table A has a value in field name A that can be matched to an instance of field name B.
An example:
| Table A = Purchases | field name A = customer number |
| Table B = Customers | field name B = customer ID |
| customer number | customer ID |
| 0 | 3 |
| 1 | 4 |
| 2 | 5 |
The problem with the data frequently occurs when test data is entered by hand and it's hard to keep track of the automatically created Primary Keys.
