SAP HANA : Triggers Before Update

Example Of Trigger Before Update:

Scenario:

            Whenever I update Unit price in my “PRODUCT TRIGGER” table. The old record should be inserted on the “PRODUCT PRICE HISTORY” table.

Here I have two table named as Product Trigger table and Product Price History table:

PRODUCT PRICE HISTORY Table 

PRODUCT TRIGGER Table

Now, I’m Trying to create a trigger with the concept whenever I updating in a “PRODUCT TRIGGER” table, the old record in the “PRODUCT TABLE” will be inserted in the “PRODUCT PRICE HISTORY” table based on “PRODUCT TRIGGER” table  “UNIT PRICE” with the time.

Code:

/*---------------------------------------------------------*/

CREATE trigger "KABIL_PRACTICE"."TRIGGER price_history_trigger"

BEFORE UPDATE OF unit_price

ON "KABIL_PRACTICE"."product_Trigger"  referencing old row as old

FOR EACH ROW

BEGIN

INSERT INTO "KABIL_PRACTICE"."product_price_history" VALUES

(

:old.product_id,

:old.product_name,

:old.supplier_name,

:old.unit_price,

Current_timestamp );

END;

          /*-----------------------------------------------------------*/

 Now update a record in PRODUCT TRIGGER table:

Code:

      update "KABIL_PRACTICE"."product_Trigger" set unit_price = 850 where product_id = 2;

Results:

SAP HANA : Triggers After

v  This statement is used to triggers which is a set of statements that are executed when a given operation (INSERT/UPDATE/DELETE) takes place on a given subject table or subject view.

v  A trigger is also a stored procedure that automatically executes when an event happens on a given table or view.