Integrity Constraint Violation

From NeoWiki

---

Revision as of 10:51, 23 August 2008

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.