- 21.9.7 C API Prepared Statement Function Descriptions
- 21.9.7.1 mysql_stmt_affected_rows()
- 21.9.7.2 mysql_stmt_attr_get()
- 21.9.7.3 mysql_stmt_attr_set()
- 21.9.7.4 mysql_stmt_bind_param()
- 21.9.7.5 mysql_stmt_bind_result()
- 21.9.7.6 mysql_stmt_close()
- 21.9.7.7 mysql_stmt_data_seek()
- 21.9.7.8 mysql_stmt_errno()
- 21.9.7.9 mysql_stmt_error()
- 21.9.7.10 mysql_stmt_execute()
- 21.9.7.11 mysql_stmt_fetch()
- 21.9.7.12 mysql_stmt_fetch_column()
- 21.9.7.13 mysql_stmt_field_count()
- 21.9.7.14 mysql_stmt_free_result()
- 21.9.7.15 mysql_stmt_init()
- 21.9.7.16 mysql_stmt_insert_id()
- 21.9.7.17 mysql_stmt_next_result()
- 21.9.7.18 mysql_stmt_num_rows()
- 21.9.7.19 mysql_stmt_param_count()
- 21.9.7.20 mysql_stmt_param_metadata()
- 21.9.7.21 mysql_stmt_prepare()
- 21.9.7.22 mysql_stmt_reset()
- 21.9.7.23 mysql_stmt_result_metadata()
- 21.9.7.24 mysql_stmt_row_seek()
- 21.9.7.25 mysql_stmt_row_tell()
- 21.9.7.26 mysql_stmt_send_long_data()
- 21.9.7.27 mysql_stmt_sqlstate()
- 21.9.7.28 mysql_stmt_store_result()
my_bool mysql_stmt_attr_set(MYSQL_STMT *stmt, enum
enum_stmt_attr_type option, const void *arg)
Description
Can be used to affect behavior for a prepared statement. This function may be called multiple times to set several options.
The option argument is the option that you
want to set. The arg argument is the value
for the option. arg should point to a
variable that is set to the desired attribute value. The
variable type is as indicated in the following table.
The following table shows the possible option
values.
| Option | Argument Type | Function |
STMT_ATTR_UPDATE_MAX_LENGTH |
my_bool * |
If set to 1, causes
mysql_stmt_store_result()
to update the metadata
MYSQL_FIELD->max_length value. |
STMT_ATTR_CURSOR_TYPE |
unsigned long * |
Type of cursor to open for statement when
mysql_stmt_execute() is
invoked. *arg can be
CURSOR_TYPE_NO_CURSOR (the default)
or CURSOR_TYPE_READ_ONLY. |
STMT_ATTR_PREFETCH_ROWS |
unsigned long * |
Number of rows to fetch from server at a time when using a cursor.
*arg can be in the range from 1 to
the maximum value of unsigned long.
The default is 1. |
If you use the STMT_ATTR_CURSOR_TYPE option
with CURSOR_TYPE_READ_ONLY, a cursor is
opened for the statement when you invoke
mysql_stmt_execute(). If there
is already an open cursor from a previous
mysql_stmt_execute() call, it
closes the cursor before opening a new one.
mysql_stmt_reset() also closes
any open cursor before preparing the statement for re-execution.
mysql_stmt_free_result() closes
any open cursor.
If you open a cursor for a prepared statement,
mysql_stmt_store_result() is
unnecessary, because that function causes the result set to be
buffered on the client side.
Return Values
Zero if successful. Nonzero if option is
unknown.
Errors
None.
Example
The following example opens a cursor for a prepared statement and sets the number of rows to fetch at a time to 5:
MYSQL_STMT *stmt;
int rc;
unsigned long type;
unsigned long prefetch_rows = 5;
stmt = mysql_stmt_init(mysql);
type = (unsigned long) CURSOR_TYPE_READ_ONLY;
rc = mysql_stmt_attr_set(stmt, STMT_ATTR_CURSOR_TYPE, (void*) &type);
/* ... check return value ... */
rc = mysql_stmt_attr_set(stmt, STMT_ATTR_PREFETCH_ROWS,
(void*) &prefetch_rows);
/* ... check return value ... */
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