Duplicate Rows in Tables
A table contains duplicate rows when two or more rows are identical.
When you create a table, you can specify the handling of duplicate rows. By default, duplicate rows are allowed. If you disallow them, an error is generated when a user attempts to insert a duplicate row into a table.
In Director or VDBA, click Options in the New Table tap or Create Table dialog, respectively. This opens the Options dialog, which contains a Duplicates check box.
Note: Duplicate rows are enforced only when the table has a keyed storage structure. Storage structures are described in the chapter “Choosing Storage Structures and Secondary Indexes.”
Depending on whether duplicates are allowed, the following tasks are performed differently:
• Restructuring or relocating a table with the MODIFY statement or the equivalent operation in VDBA
• Adding new rows into a table with the INSERT statement
• Bulk loading a table with the COPY statement
• Revising existing rows in a table with the UPDATE command