There are a number of restrictions on queue tables, as detailed in the following list.
- You cannot change a queue table into a non-queue table.
- You cannot modify the first column defined for a queue table to be something other than a user-defined QITS column (see QITS Column).
- You cannot drop the QITS column from a queue table.
- You cannot modify the QITS column by adding either of the following attributes.
- UNIQUE
- PRIMARY KEY
Because of this restriction, you cannot add a simple UPI on the QITS column.
Similarly, you cannot modify the QITS column to make it a simple UPI.
- You cannot add either of the following constraints to a queue table definition.
- FOREIGN KEY … REFERENCES
- REFERENCES
- You cannot modify any column of a queue table to have a LOB data type (see Teradata Vantage™ - Data Types and Literals, B035-1143).
- You cannot add a permanent journal to the definition for a queue table.
- You cannot add a reference to queue table columns in a REFERENCES clause for any table.
Otherwise, all column- and table-level constraint clauses are valid within queue table definitions with the exception of UNIQUE and PRIMARY KEY constraints not being valid attributes for the QITS column.
- You cannot modify a queue table definition to have a partitioned primary index.