pdo_stmt_t definition


All fields should be treated as read-only unless explicitly stated otherwise.

/* represents a prepared statement */ struct _pdo_stmt_t {     /* driver specifics */     struct pdo_stmt_methods *methods;
*
void *driver_data;
**
/* 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; };
*

The driver must set this during SKEL_handle_preparer().

**

This item is for use by the driver; the intended usage is to store a pointer (during SKEL_handle_factory()) to whatever instance data is required to maintain a connection to the database.

***

This is set by PDO after the statement has been executed for the first time. Your driver can inspect this value to determine if it can skip one-time actions as an optimization.

****

Discussed in more detail in SKEL_handle_preparer.

*****

Your driver is responsible for setting this field to the number of columns available in a result set. This is usually set during SKEL_stmt_execute() but with some database implementations, the column count may not be available until SKEL_stmt_fetch() has been called at least once. Drivers that implement SKEL_stmt_next_rowset() should update the column count when a new rowset is available.

******

PDO will allocate this field based on the value that you set for the column count. You are responsible for populating each column during SKEL_stmt_describe(). You must set the precision, maxlen, name, namelen and param_type members for each column. The name is expected to be allocated using emalloc(); PDO will call efree() at the appropriate time.