PostgreSQL

SPI_execute_with_args
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SPI_execute_with_args

SPI_execute_with_args — execute a command with out-of-line parameters

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 + Ifnulls 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.
+bool +`+read_only+`: true for read-only execution
+long +`+count+`: maximum number of rows to return, or 0 for no limit

Return Value

The return value is the same as for SPI_execute.

SPI_processed and SPI_tuptable are set as in SPI_execute if successful.

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