November 2008
Intermediate to advanced
591 pages
17h 28m
English
Constraints may be applied at the column level or the table level:
Are declared as part of a column definition and apply only to that column.
Are declared independently from any column definitions (traditionally, at the end of a CREATE TABLE statement) and may apply to one or more columns in the table. A table constraint is required when you wish to define a constraint that applies to more than one column.