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 --²éѯÊý¾Ý
SELECT *
from main_table;
--Ìí¼ÓÊôÐÔ
ALTER TABLE main_table
ADD AcctStop_Time SMALLDATETIME NULL;
--²åÈëÐÂÊý¾Ý
INSERT INTO main_table(Digital_ID, Letter_ID, User_Password, On_Line, IP, AcctStop_Time, FriendTable_UpdaeTime)
VALUES(10000000 + IDENT_CURRENT('main_table') + IDENT_INCR('main_table'), 'ttl', 666666, 0, 192168001025, GetDate(),GetDate());
--ÐÞ¸ÄÐÐÐÅÏ¢
UPDATE main_table
SET Digital_ID = 1000000+3, Letter_ID = 'ttoob'
WHERE Digital_Mark = 3
--Ìí¼ÓΨһÐÔÔ¼Êø
ALTER TABLE main_table
ADD CONSTRAINT user_id_key UNIQUE(Digital_ID);
--ɾ³ýΨһÐÔÔ¼Êø
ALTER TABLE main_table
DROP CONSTRAINT user_id_key
--»ñµÃ±í½á¹¹       SQLServer2000Ï¿ÉÓá£
exec   sp_columns   '±íÃû'