|Child Table||A table where the referential constraints are defined.
Child table and referencing table are synonyms.
|Parent Table||The table referenced by a child table.
Parent table and referenced table are synonyms.
UNIQUE Alternate Key
|A unique identifier for a row of a table.|
|Foreign Key||A column set in the child table that is also the primary key (or a UNIQUE alternate key) in the parent table.
Foreign keys can consist of as many as 64 different columns.
|Referential Constraint||A constraint defined on a column set or a table to ensure referential integrity.
For example, consider the following table definition:
CREATE TABLE A (A1 CHAR(10) REFERENCES B (B1), /* 1 */ A2 INTEGER FOREIGN KEY (A1,A2) REFERENCES C /* 2 */ PRIMARY INDEX (A1));
This CREATE TABLE statement specifies the following referential integrity constraints.