You can specify constraints during table creation and modification.
Column constraints apply to single columns as a part of the column definition. Column constraints include:
- CHECK constraint definition clause on a single column
- PRIMARY KEY constraint definition clause on a single column
- REFERENCES constraint definition clause on a single column
- UNIQUE constraint definition clause
Table constraints apply to multiple columns. Table-level constraints include:
- CHECK constraint definition clause on multiple columns
- REFERENCES constraint definition clause on multiple columns
- PRIMARY KEY constraint definition clause on multiple columns
- UNIQUE constraint definition clause on multiple columns
- FOREIGN KEY constraint definition clause
FOREIGN KEY constraint definitions must also specify a REFERENCES clause.
The full syntax for constraints is in ALTER TABLE and CREATE TABLE in Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144