MySQL Trigger trigger usage one (simple)

Example ~ ~

example1:

Create a table Tab1

1234	DROPTABLE IF EXISTS tab1;CREATE TABLEtab1(    tab1_id varchar(11));

Create a table TaB2

1234	DROPTABLE IF EXISTS tab2;CREATE TABLEtab2(    tab2_id varchar(11));

Create trigger:t_afterinsert_on_tab1

Function: Automatically adds records to the TAB2 table after adding TAB1 table records

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DROPTRIGGER IF EXISTS t_afterinsert_on_tab1;CREATE TRIGGER t_afterinsert_on_tab1 AFTER INSERT ON tab1FOR EACH ROWBEGIN     insert intotab2(tab2_id) values(new.tab1_id);END;

Test it.

1	INSERTINTOtab1(tab1_id) values(‘0001‘);

Look at the results

12	SELECT* FROM tab1;SELECT * FROMtab2;

example2:

Create trigger:t_afterdelete_on_tab1

Function: Delete the TAB1 table records automatically deleted the corresponding records in the TAB2 table

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DROPTRIGGER IF EXISTS t_afterdelete_on_tab1;CREATE TRIGGER t_afterdelete_on_tab1AFTER DELETE ON tab1FOR EACH ROWBEGIN      delete from tab2 wheretab2_id=old.tab1_id;END;

Test it.

1	DELETEFROM tab1 WHEREtab1_id=‘0001‘;

MySQL Trigger trigger usage one (simple)