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发布时间：1714920961
Column-levelAuthorization
ThefollowingcommandgrantsaroletheSELECTprivilegeonacolumn:
GRANTSELECT(column_nameONTABLEtable_nameTOROLErole_name;
ThefollowingcommandcanbeusedtorevoketheSELECTprivilegeonacolumn:
REVOKESELECT(column_nameONTABLEtable_nameFROMROLErole_name;
Anynewcolumnsaddedtoatablewillbeinaccessiblebydefault,untilexplicitlygrantedaccess.
ActionsallowedforuserswithSELECTprivilegeonacolumn:
UserswhoseroleshavebeengrantedtheSELECTprivilegeoncolumnsonly,canperformoperationswhichexplicitlyrefertothosecolumns.Someexamplesare:
•
SELECTcolumn_nameFROMTABLEtable_name;
Inthiscase,Sentrywillfirstchecktoseeiftheuserhastherequiredprivilegestoaccessthetable.Itwillthenfurtherchecktoseewhethertheuserhas
theSELECTprivilegetoaccessthecolumn(s.
•
SELECTCOUNT(column_nameFROMTABLEtable_name;
UsersarealsoallowedtousetheCOUNTfunctiontoreturnthenumberofvaluesinthecolumn.
•
SELECTcolumn_nameFROMTABLEtable_nameWHEREcolumn_name
GROUPBYcolumn_name;
Theabovecommandwillworkaslongasyoureferonlytocolumnstowhichyoualreadyhaveaccess.
•Tolistthecolumn(stowhichthecurrentuserhasSELECTaccess:
SHOWCOLUMNS;
Exceptions:
•IfauserhasSELECTaccesstoallcolumnsinatable,thefollowingcommand
willwork.Notethatthisisanexception,notthenorm.Inallothercases,SELECTonallcolumnsdoesnotallowyoutoperformtable-leveloperations.
SELECT*FROMTABLEtable_name;
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