/* represents a prepared statement */
struct _pdo_stmt_t {
/* driver specifics */
struct pdo_stmt_methods *methods;
***
/* if true, we've already successfully executed this statement at least
* once */
unsigned executed:1;
***
/* if true, the statement supports placeholders and can implement
* bindParam() for its prepared statements, if false, PDO should
* emulate prepare and bind on its behalf */
unsigned supports_placeholders:2;
****
/* the number of columns in the result set; not valid until after
* the statement has been executed at least once. In some cases, might
* not be valid until fetch (at the driver level) has been called at least once.
* */
int column_count;
*****
struct pdo_column_data *columns;
******
/* points at the dbh that this statement was prepared on */
pdo_dbh_t *dbh;
/* keep track of bound input parameters. Some drivers support
* input/output parameters, but you can't rely on that working */
HashTable *bound_params;
/* When rewriting from named to positional, this maps positions to names */
HashTable *bound_param_map;
/* keep track of PHP variables bound to named (or positional) columns
* in the result set */
HashTable *bound_columns;
/* not always meaningful */
long row_count;
/* used to hold the statement's current query */
char *query_string;
int query_stringlen;
/* the copy of the query with expanded binds ONLY for emulated-prepare drivers */
char *active_query_string;
int active_query_stringlen;
/* the cursor specific error code. */
pdo_error_type error_code;
/* used by the query parser for driver specific
* parameter naming (see pgsql driver for example) */
const char *named_rewrite_template;
};