This clause defines the table column elements.
You must specify a name and data type for each column defined for a table. When you create a table copy using the CREATE TABLE … AS syntax, you either carry over the source table column types by default or specify new column data types using a query expression. Each data type can be further defined with one or more attribute definitions.
You can specify the following optional column attributes:
- Data type attribute declaration
- Column nullability
- Multivalue and algorithmic compression
- Column storage attributes
- Output format attributes
- Default value attributes
See Teradata Vantage™ - Data Types and Literals, B035-1143 for details about the preceding list of attributes.
- Column constraint attributes
- PRIMARY KEY constraint definition
- UNIQUE constraint definition
- FOREIGN KEY ... REFERENCES constraint definition
- CHECK constraint definition
- Row-level security constraint assignments.
You can also specify PRIMARY KEY, UNIQUE, FOREIGN KEY, and CHECK constraints as table attributes, but you cannot specify a row-level security constraint as a table attribute.