Purpose

Defines a constraint for a remote table.

Syntax

[CONSTRAINT [constraint_name] {foreign_key_constraint}]

where:

constraint_name
is ignored. The driver uses the Salesforce relationship naming convention to generate the constraint name.
foreign_key_constraint
defines a link between related tables. See "Foreign Key Clause" for the syntax.
A column defined as a foreign key in one table references a primary key in the related table. Only values that are valid in the primary key are valid in the foreign key. The following example is valid because the foreign key values of the dept id column in the EMP table match those of the id column in the referenced table DEPT:
Referenced Table Main Table
DEPT EMP
(Foreign Key)
id name id name dept id
1 Dev 1 Mark 1
2 Finance 1 Jim 3
3 Sales 1 Mike 2
The following example, however, is not valid. The value 4 in the dept id column does not match any value in the referenced id column of the DEPT table.
Referenced Table Main Table
DEPT EMP
(Foreign Key)
id name id name dept id
1 Dev 1 Mark 1
2 Finance 1 Jim 3
3 Sales 1 Mike 4