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

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.

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.