SPI_execute_with_args
Synopsis
int SPI_execute_with_args(const char *command,
int nargs, Oid *argtypes,
Datum *values, const char *nulls,
bool read_only, long count)
Description
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.
Arguments
- const char * command
-
command string
- int nargs
-
number of input parameters ($1, $2, etc.)
- Oid * argtypes
-
an array of length nargs, containing the OIDs of the data types of the parameters
- Datum * values
-
an array of length nargs, containing the actual parameter values
- const char * nulls
-
an array of length nargs, describing which parameters are null
If nulls is NULL then
SPI_execute_with_argsassumes 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. - bool read_only
-
true for read-only execution
- long count
-
maximum number of rows to return, or 0 for no limit