Dropping Tables with Cross-Database Referential Integrity Constraints

When you create a cross-database constraint, the SAP ASE server stores information in the sysreferences system table of each database.

Information Stored About Referential Integrity Constraints
Information Stored in `sysreferences`	Columns with Information About Referenced Table	Columns with Information About Referencing Table
Key column IDs	`refkey1` through `refkey16`	`fokey1` through `fokey16`
Table ID	`reftabid`	`tableid`
Database name	`pmrydbname`	`frgndbname`

Because the referencing table depends on information from the referenced table, the SAP ASE server does not allow you to:

Drop the referenced table,
Drop the external database that contains it, or
Use sp_renamedb to rename either database.

Use sp_helpconstraint to determine which tables reference the table you want to drop. Use alter table to drop the constraints before reissuing drop table.

You can drop a referencing table or its database. The SAP ASE server automatically removes the foreign-key information from the referenced database.

Each time you add or remove a cross-database constraint or drop a table that contains a cross-database constraint, dump both of the affected databases.

Warning! Loading earlier dumps of these databases can cause database corruption. For more information about loading databases with cross-database referential integrity constraints, see the System Administration Guide.