Composite key

A composite key is a key (primary or alternate) that consists of more than one column. Oracle will create a composite key index on the table to implement and enforce the composite key. Composite keys are also known as concatenated or aggregate keys.

Example

For example, the LINE_ITEMS table may have composite keys on {orderID, itemNumber} and {orderID, productId}:

CREATE TABLE line_items (
  orderID    NUMBER,
  itemNumber NUMBER,
  productId  NUMBER,
  quantity   NUMBER,
  PRIMARY KEY (orderID, itemNumber),
  UNIQUE (orderID, productId));

Also see

• Primary key
• Candidate key

Glossary of Terms
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