Joe Celko's SQL for Smarties, 3rd Edition

18.6. Dropping VIEWs

VIEWs, like tables, can be dropped from the schema. The Standard SQL syntax for the statement is:

DROP VIEW <table name> <drop behavior>

<drop behavior> ::= [CASCADE | RESTRICT]

The <drop behavior> clause did not exist in SQL-86, so vendors had different behaviors in their implementation. The usual way of storing VIEWs was in a schema-level table with the VIEW name, the text of the VIEW, and other information. When you dropped a VIEW, the engine usually removed the appropriate row from the schema tables. You found out about dependencies when you tried to use VIEWs built on other VIEWs that no longer existed. Likewise, dropping a base table could cause the same problem when the VIEW was accessed.

The CASCADE option will find ...