Validating constraints and oracle

15-Feb-2020 10:21 by 3 Comments

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Oracle Check Constraint Oracle check constraint insures that updated or inserted values meet a specific condition.The Oracle check constraint check condition must return a TRUE or FALSE, much Like the WHERE clause.

I know there are presently rows that violates this constraint (meaning, there are duplicate rows). U_SMCSHIPPING ENABLE NOVALIDATE CONSTRAINT CHASE_NUM_UNIQUE; Got the same error msg: ORA-02299: cannot validate (EMPOWER.Now that our business rules have changed, I do not want any duplicate rows to be inserted. The error message will not tell you which rows are the cause of this error.With Oracle check constraint, rather than having an application verify that all occurrences of REGION are North, South, East, or West, an Oracle CHECK constraint can be added to the table definition to ensure the validity of the region column.Here is an example of Oracle check constraint: Oracle check constraint has some limitations.The same goes for adding a foreign key constraint on table column (or columns) which requires an parent key to exist, you will get an error like : Of course you can write some query to figure out which rows are duplicate in the table or which parent keys are missing when you receive an constraint validation error when trying to add or enable a foreign key constraint, but it can be easier (and faster) to use a so called For each row causing problems there will be one row in this exception table.

The exception table only contains the rowid of the problem row, so you have join the exceptions table with the the table you are adding or enabling the constraint for to get the troubling rows.

Sysdate, currval, nextval, level, rowid, uid, user or userenv cannot be referenced with Oracle check constraint.

Oracle check constraint cannot reference columns from other tables.

Locking behaviour depends on whether foreign key columns are indexed.

If foreign keys are not indexed, then the child table will probably be locked more frequently, deadlocks will occur, and concurrency will be decreased.

in Subquery all the columns that will be checked for duplication...