The document number generated by the oracle trigger and the oracle trigger

The document number generated by the oracle trigger and the oracle trigger
Create or replace trigger TRG_KC_SPRK_ I
Before insert on KC_SPRK
FOR EACH ROW
DECLARE
VSCBH varchar2 (40 );
ICount NUMBER;
IFor number;
BEGIN
Select t. bhqz into vSCBH from xt_djbhgz t where t.gz id = 8; -- obtain a field of another table as the prefix, or assign a value directly to the field: vSCBH: = 'gxcb _'
Select count (1) + 1 INTO iCount from KC_SPRK j where j. xzsj> = trunc (sysdate, 'mm'); -- obtain the total number of tables in this table + 1 and assign the value to iCount.
VSCBH: = vSCBH | to_char (sysdate, 'yyyymm'); -- prefix + date and year
FOR iFor IN 1 .. 5-LENGTH (iCount) LOOP
VSCBH: = vSCBH | '0 ';
End loop;
: New. RK_DJH: = vSCBH | iCount;

END TRG_KC_SPRK_ I;

Result: GXCB_20141100001 GXCB_20141100002 GXCB_20141100003