foreign key relationship, in that the reference table (foreign key table) is null

[jacob deiter]

I see a foreign key relationship, in that the reference table (foreign key table) is null but it has foreign value key. So what type of constraint it is?
EX:
ALTER TABLE XXXXX.XXXXXXXX
ADD FOREIGN KEY (ABCDEF)
REFERENCES null (null);
DB: Oracle.

[Brian Tkatch]

Sounds odd. REFERENCES must specify a TABLE, and optionally, a COLUMN. Are you're rights restricted in the DB?

Run this query in SQLPlus and pass the tablename when asked:
COLUMN "Column" FORMAT A30 COLUMN "#" FORMAT A1 COLUMN "Other Table" FORMAT A30 COLUMN "Other Column" FORMAT A30 SELECT CASE Type WHEN 'C' THEN 'Child' ELSE 'Parent' END "End", CASE Type WHEN 'C' THEN Child_Column ELSE Parent_Column END "Column", SubStr(Position, 1, 1) "#", CASE Type WHEN 'C' THEN Parent_Table ELSE Child_Table END "Other Table", CASE Type WHEN 'C' THEN Parent_Column ELSE Child_Column END "Other Column", Constraint_Name "Constraint" FROM ( SELECT ( CASE WHEN Child_Columns.Table_Name = UPPER('&1') THEN 'C' ELSE 'P' END ) Type, Constraints.Constraint_Name Constraint_Name, Constraints.R_Constraint_Name R_Constraint_Name, Parent_Columns.Position Position, Parent_Columns.Table_Name Parent_Table, Parent_Columns.Column_Name Parent_Column, Child_Columns.Table_Name Child_Table, Child_Columns.Column_Name Child_Column FROM All_Constraints Constraints, All_Cons_Columns Parent_Columns, All_Cons_Columns Child_Columns WHERE ( Parent_Columns.Table_Name = UPPER('&1') OR Child_Columns.Table_Name = UPPER('&1') ) AND Constraints.Constraint_Type = 'R' -- Join Parent_Columns to get the COLUMN names. AND Parent_Columns.Owner = Constraints.R_Owner AND Parent_Columns.Constraint_Name = Constraints.R_Constraint_Name -- Join Child_Columns to get the COLUMN names. AND Child_Columns.Owner = Constraints.Owner AND Child_Columns.Constraint_Name = Constraints.Constraint_Name AND Child_Columns.Position = Parent_Columns.Position ) ORDER BY Type, Constraint_Name, "#";

[Roel De Nijs]

jacob deiter wrote:I see a foreign key relationship, in that the reference table (foreign key table) is null but it has foreign value key. So what type of constraint it is?

Are you really sure? Because that makes no sense at all. Why would you add a FK if you don't define a reference table?