SQL/MX Programming Manual for C and COBOL (G06.24+, H06.03+)

Static SQL Cursors
HP NonStop SQL/MX Programming Manual for C and COBOL—523627-004
6-2
Steps for Using a Static SQL Cursor
Steps for Using a Static SQL Cursor
Figure 6-1 shows the steps presented within the complete C program. These steps are
executed in the sample program Example A-1 on page A-1.
Note. Using a cursor can sometimes degrade performance. A cursor requires OPEN, FETCH,
and CLOSE statements, which increase the number of messages between the HP NonStop
Distribution Service (DS) and the HP NonStop Data Access Manager (DAM). Consider not
using a cursor if a single-row retrieval is sufficient.
Figure 6-1. Using a Static SQL Cursor in a C Program
...
EXEC SQL BEGIN DECLARE SECTION;
int hostvar;
...
EXEC SQL END DECLARE SECTION;
...
EXEC SQL DECLARE sql_cursor CURSOR FOR
SELECT column_1, column_2, ..., column_n
FROM catalog.schema.table
WHERE column_1 = :hostvar;
...
void find_row(void)
{
...
hostvar = initial_value;
...
EXEC SQL OPEN sql_cursor;
...
EXEC SQL FETCH sql_cursor
INTO :hostvar_1, :hostvar_2, ..., :hostvar_n;
...
... /* Process values in the host variable(s). */
...
... /* If last row has not been processed, */
/* branch back to fetch another row. */
...
EXEC SQL CLOSE sql_cursor;
...
} /* end find_row
...
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