Question

I have written following piece of code in C:

EXEC SQL begin declare section;
    int     A;
    char    B[5];
    int     C;
    int     D;
    dtime_t E;
    char    F[13];
EXEC SQL END DECLARE SECTION;
char E_dt[16];
D=0;
memset(F, 0, sizeof(F));          

EXEC SQL declare log3 cursor for select A, B, C, D, E, F from tbl WHERE C=123;
if(sqlca.sqlcode) 
{
    return;
}

EXEC SQL fetch log3
    into
     :A, :B, :C, :D, :E, :F, 
if(sqlca.sqlcode) 
{
    if (sqlca.sqlcode != DB_NORECORDS) 
    {
        return;
    }
    break;
}

When we run this piece of code, where the value of F is Null in the table tbl. It gives error code 1405. I have tried memset function for setting its default value as 0. But it did not work. And one more thing can i fetch more than 90 field at a time, when i was trying to do that it gives me Bus Error at the time of compilation. Thanks in advance please help me out.

Answer 1

You have 2 basic options:

1. Use an indicator to record the presence of the NULL. You probably should use this option when you want a specific action to be taken when a NULL arises.
2. Use the NVL function to convert the retrieved NULL to another value, such as zero or blank. This is the simplest solution.

Edit:

Example with NVL for log3 cursor. Choose whatever default values you want. In the example I have used ‘ ‘ for character fields, 0 for numeric fields and Jan 1st year 1 for dates.

EXEC SQL declare log3 cursor for select NVL(A, 0), 
                                        NVL(B, ' '), 
                                        NVL(C, 0), 
                                        NVL(D, 0), 
                                        NVL(E, to_date('0001', 'YYYY')),
                                        NVL(F, ' ')
                                   from tbl 
                                  WHERE C=123;