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