为什么我的光标无限循环到最后一行

Question

Hello I've been trying to use a cursor with embedded sql in c but I can't seem to get it to stop reading the last row in my table. The table is called publication with two attributes pubid and title. I just want my cursor to iterate through and display the pubid. This is what i have:

    EXEC SQL DECLARE C1 CURSOR FOR SELECT pubid FROM publication;
    EXEC SQL OPEN C1;
    while(SQLCODE !=100){
        EXEC SQL FETCH C1 INTO :pubid; //a host variable that was declared earlier
        cout<<pubid<<endl;
    }

When I run, it displays all the rows and infinitely repeats displaying the last row. I tried displaying the SQLCODE as well and it remains 0, so I'm not sure why the cursor doesn't move past the last row

Answer 1

EXEC SQL DECLARE C1 CURSOR FOR SELECT pubid FROM publication;
EXEC SQL OPEN C1;
EXEC SQL WHENEVER NOT FOUND GOTO close_c1;
while(SQLCODE !=100) {
    EXEC SQL FETCH C1 INTO :pubid;
    cout<<pubid<<endl;
}
close_c1:
EXEC SQL CLOSE C1;

Something like this should work. Also consider using EXEC SQL WHENEVER SQLERROR clean_up_function; to be able to print out diagnostics. I found references here .