int SPI_execute_with_args(const char *command, int nargs, Oid *argtypes, Datum *values, const char *nulls, bool read_only, long count)
SPI_execute_with_args
executes a
command that might include references to externally supplied
parameters. The command text refers to a parameter as $n, and the call
specifies data types and values for each such symbol. read_only and count
have the same interpretation as in SPI_execute
.
The main advantage of this routine compared to SPI_execute
is that data values can be inserted
into the command without tedious quoting/escaping, and thus with
much less risk of SQL-injection attacks.
Similar results can be achieved with SPI_prepare
followed by SPI_execute_plan
; however, when using this
function the query plan is always customized to the specific
parameter values provided. For one-time query execution, this
function should be preferred. If the same command is to be executed
with many different parameters, either method might be faster,
depending on the cost of re-planning versus the benefit of custom
plans.
command string
number of input parameters ($1, $2, etc.)
an array of length nargs, containing the OIDs of the data types of the parameters
an array of length nargs, containing the actual parameter values
an array of length nargs, describing which parameters are null
If nulls is NULL then SPI_execute_with_args
assumes that no parameters
are null. Otherwise, each entry of the nulls array should be ' ' if the corresponding parameter value is
non-null, or 'n' if the corresponding
parameter value is null. (In the latter case, the actual value in
the corresponding values entry doesn't
matter.) Note that nulls is not a text
string, just an array: it does not need a '\0' terminator.
true for read-only execution
maximum number of rows to return, or 0 for no limit