sp_foreignkey

Syntax

sp_foreignkey tabname, pktabname, col1 [, col2] ... 
	[, col8]

tabname – is the name of the table or view that contains the foreign key to be defined.
pktabname – is the name of the table or view that has the primary key to which the foreign key applies. The primary key must already be defined.
col1 – is the name of the first column that makes up the foreign key. The foreign key must have at least one column and can have a maximum of eight columns.

Example 1 – The primary key of the publishers table is the pub_id column. The titles table also contains a pub_id column, which is a foreign key of publishers:
```
sp_foreignkey titles, publishers, pub_id
```
Example 2 – The primary key of the parts table has been defined with sp_primarykey as the partnumber and subpartnumber columns. The orders table contains the columns part and subpart, which make up a foreign key of parts:
```
sp_foreignkey orders, parts, part, subpart
```

There are additional considerations when using sp_foreignkey:

sp_foreignkey adds the key to the syskeys table. Keys make explicit a logical relationship that is implicit in your database design.
sp_foreignkey does not enforce referential integrity constraints; use the foreign key clause of the create table or alter table command to enforce a foreign key relationship.
The number and order of columns that make up the foreign key must be the same as the number and order of columns that make up the primary key. The datatypes (and lengths) of the primary and foreign keys must agree, but the null types need not agree.
The installation process runs sp_foreignkey on the appropriate columns of the system tables.
To display a report on the keys that have been defined, execute sp_helpkey.
You cannot use a Java datatype with sp_foreignkey.

You must be the owner of the table or view to execute sp_foreignkey. Permission checks do not differ based on the granular permissions settings.

Values in event and extrainfo columns from the sysaudits table are:

Information	Values
Event	38
Audit option	exec_procedure
Command or access audited	Execution of a procedure
Information in `extrainfo`	Roles – Current active roles Keywords or options – NULL Previous value – NULL Current value – NULL Other information – All input parameters Proxy information – Original login name, if set proxy in effect