I have two tables :
table T1 has one column C1 CHAR (30)
table T2 has one column D1 CHAR (50)
One joint select where 2 columns have different size :
select DISTINCT T1.C1 from T1, T2 where T1.C1 = T2.D1;
In my C language application, the buffer to bind the selected columns is
char myBuffer ; /* The sizeof C1 add 1 for null terminated string */
With Oracle 11, the application is OK
With Oracle 12, the application is failed due to data overflow.
If myBuffer size is increased to
char myBuffer  /* the sizeof D1 add 1 */
=> With Oracle 12, the application is also OK.
Is there an Oracle parameter or environment variable, to set the selected column size to the smaller one of the joint (30)
instead of the bigger (50), to avoid the source modification which is increasing the buffer size ?
Thank you in advance