Secondary Navigation. 1  Active Duty Dental Care. 2  Guard/Reserve Dental Care. 3  TRICARE Dental Program. 4  TRICARE Retiree Dental Program. 5  Enrolling in the TRICARE Retiree Dental Program. Costs. 6  Dental Benefits for Survivors. 7  Find a Dentist.
â¢ Although char and varchar are character data fields, char is a fixed length data field and varchar is a variable size data field. â¢ Char can store only fixed size non-Unicode string characters, but varchar can store variable sizes of strings.
VARCHAR : when u r using this data type what ever size u r giving that much of memory is allocated to that variable. suppose u r giving varcahr(20) then u enter only 15 cahracters of that variable then also it is giving memory of 20 cahracters.VARCHAR2: when u r using this data type the memory allocation is different.