Oracle9i DBA -- Database: Fundamentals I (14)

Maintaining Data Integrity
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• The utlexcptl.sql script can create the EXCEPTIONS table

• CHECK constraint can be defined at both column and table level. Environment functions such as SYSDATE cannot be used to evaluate check condition.
• Use the SET CONSTRAINTS statement to make constraints either DEFERRED or IMMEDIATE. The ALTER SESSION statement also has cluses to SET CONSTRAINTS to DEFERRED or IMMEDIATE.
• DBA_CONSTRAINTS view is required to return the name of the foreign key constraint(CONSTRAINTS_NAME) and the referenced primary key(R_CONSTRAINTS_NAME).
• Both unique and primary key constraints require index.