Oracle Version : 10g As you know inside a Oracle row trigger you cannot access to the base table, for example when you make a trigger like this, on a table named “activity“.
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CREATE OR REPLACE TRIGGER UNAME.ACTIVITY_FK_MENU_INTEGRITY AFTER INSERT OR UPDATE ON UNAME.ACTIVITY REFERENCING NEW AS New OLD AS Old FOR EACH ROW DECLARE tmpVar NUMBER; e_Menu_Already_Exists EXCEPTION; BEGIN Select count(*) into tmpVar from Activity aa where (aa.fk_menu = :new.fk_menu)and(aa.pk_id <> :new.pk_id); -- if (tmpVar > 0) then --:New.FK_MENU := null; -- raise e_Menu_Already_Exists; -- end if; END ACTIVITY_FK_MENU_INTEGRITY; |
when you try to use the table making an update happen this : To avoid this error and obviusly assuming the…
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by using some simple view in Oracle you can extract a lot of information about your DB schema, some explicit samples : (assuming that MyDBOwner is the owner of the DB and ACTIVITY is a table of a schema, this sample is succesfully tested on Oracle 10g)
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-- LIST OF USERS select OWNER,COUNT(DISTINCT TABLE_NAME) from ALL_TAB_COLUMNS GROUP BY OWNER -- LIST OF TABLES PER OWNER select table_name from ALL_TAB_COLUMNS where owner = 'MyDBOwner' group by table_name -- LIST OF FIELDS PER TABLE select COLUMN_NAME, DATA_TYPE, DATA_LENGTH, NULLABLE, CHAR_LENGTH from ALL_TAB_COLUMNS where owner = 'MyDBOwner' AND TABLE_NAME = 'ACTIVITY' -- FINDING PRIMARY KEYS select COLUMN_NAME, DATA_TYPE, DATA_LENGTH, NULLABLE, CHAR_LENGTH from ALL_TAB_COLUMNS where owner = 'MyDBOwner' AND TABLE_NAME = 'ACTIVITY' -- A single character that indicates the type of constraint: 'C' = NOT NULL, 'P' = PRIMARY KEY, 'U' = UNIQUE, and 'R' = FOREIGN KEY. SELECT UC.CONSTRAINT_NAME, UCC.* FROM USER_CONSTRAINTS UC, USER_CONS_COLUMNS UCC WHERE UC.OWNER='MyDBOwner' AND UC.TABLE_NAME = 'ACTIVITY' AND UC.CONSTRAINT_TYPE = 'P' AND UC.CONSTRAINT_NAME = UCC.CONSTRAINT_NAME |
a great article about this is :…
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Sometime,appen is required to produce an Xml Document where you can’t have a good Xml parser or for perfomance you can’t use that , so you need to encode and decode it manually to produce or read a standard document. Assuming thay you need create a simple Xml file like : Worng Xml file :…
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