mysql_stmt_attr_get

mysql_stmt_attr_get retrieves the current value of a prepared statement attribute, such as cursor type, prefetch row count, or max-length update behavior.

Syntax

my_bool mysql_stmt_attr_get(MYSQL_STMT * stmt,
                            enum enum_stmt_attr_type,
                            void * attr);

Parameters

Parameter	Description
stmt	A statement handle, which was previously allocated by mysql_stmt_init().
enum_stmt_attr_type	Attribute. See Attribute Types.
attr	Pointer to a variable, which will contain the attribute value.

Description

Gets the current value of a statement attribute. Returns zero on success, non zero on failure.

Attribute Types

The enum_stmt_attr_type parameter has the following possible values:

• STMT_ATTR_UPDATE_MAX_LENGTH: Indicates if mysql_stmt_store_result() will update the max_length value of MYSQL_FIELD structures.

  my_bool is_update;
  rc= mysql_stmt_attr_get(stmt, STMT_ATTR_UPDATE_MAX_LENGTH, &is_update);

• STMT_ATTR_CURSOR_TYPE: Cursor type. Possible values are CURSOR_TYPE_READ_ONLY or default value CURSOR_TYPE_NO_CURSOR.

  unsigned long cursor_type;
  rc= mysql_stmt_attr_get(stmt, STMT_ATTR_CURSOR_TYPE, &cursor_type);

• STMT_ATTR_PREFETCH_ROWS: Number of rows which will be prefetched. The default value is 1.

  unsigned long prefetch_rows;
  rc= mysql_stmt_attr_get(stmt, STMT_ATTR_PREFETCH_ROWS, &prefetch_rows);

• STMT_ATTR_PREBIND_PARAMS: Number of parameters used for mariadb_stmt_execute_direct()

  unsigned int param_count;
  rc= mysql_stmt_attr_get(stmt, STMT_ATTR_PREBIND_PARAMS, ¶m_count);

• STMT_ATTR_STATE: Status of the prepared statement. The returned value is of type enum mysql_stmt_state. Possible values are defined in enum mysql_stmt_state. Introduced in MariaDB Connector/C 3.1.0

  enum mysql_stmt_state stmt_state; 
  rc= mysql_stmt_attr_get(stmt, STMT_ATTR_STATE, &stmt_state); 

• STMR_ATTR_SQL_STATEMENT: The SQL statement from the last executed mysql_stmt_prepare() call. The returned value is of type MARIADB_CONST_STRING. Added in MariaDB Connector/C 3.4.4

  MARIADB_CONST_STRING sql_statement; 
  rc= mysql_stmt_attr_get(stmt, STMR_ATTR_SQL_STATEMENT, &sql_statement);

Setting the number of prefetched rows will work only for read only cursors.

See Also

• mysql_stmt_attr_set()