Wednesday, April 18, 2007

Oracle9i DBA -- Database: Fundamentals I (14)

Maintaining Data Integrity

  • 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.

Read more!

No comments: