Primary Key Field Type
 ID int

Field Field Type Null Notes Description
 Password nvarchar(255)
 DateUsed datetime Default = getutcdate()

Foreign Key Field Type Null Notes Description
 UserID int   ClientUsers.ID

Index Name Field(s) Unique Primary Clustered
 IX_ClientUserPasswordHistory_UserID_DateUsed UserID, DateUsed (DESC)      
 PK_PASSWORDHISTORY ID

Entity-Relationship diagram of this table