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Checking update statement

The procedure of checking access rights for update is exactly the same like this defined for the insert. The differences are only in steps 2 and 4. In step 2, the parameter action for the WHERE caluse is defined as UPDATE. In step 4 descriptors are compared with the values of record which will be updated by the user (in the INSERT they are compared with the values which are introduced by the user).

Examples:

(1) UPDATE breeds SET breed_id='50000045',mcname='new mcname'
      WHERE breed_id=444446;
(2) UPDATE animal SET birth_dt='2000-09-02', db_sex=73
      WHERE db_animal=444556;
(3) UPDATE animal SET birth_dt='2000-09-02', name='some name' 
      WHERE db_animal>1 and db_animal<10 and db_sex=73;

In our examples the first update can be executed if the tax_id of existing record is defined as 5 or 6 or 7. The second update can not be executed because db_animal is out of the range. The third record can be also not executed because action is allowed only for the records where db_sex has 72 value (in this case db_animal is correct).



Marek Imialek 2006-06-22