Función de tabla simple en lenguaje C

El código de este ejemplo crea una función que divide una cadena en varias cadenas en función del delimitador. Este ejemplo puede devolver más filas de salida que de entrada. Observe la lógica de bucle adicional en ejecución.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "nzaeapis.h"
static int run(NZAE_HANDLE h);
int main(int argc, char * argv[])
{
if (nzaeIsLocal())
{
NzaeInitialization arg;
memset(&arg, 0, sizeof(arg));
arg.ldkVersion = NZAE_LDK_VERSION;
if (nzaeInitialize(&arg))
{
fprintf(stderr, "initialization failed\n");
return -1;
}
run(arg.handle);
nzaeClose(arg.handle);
}
else {
NZAECONPT_HANDLE hConpt = nzaeconptCreate();
if (!hConpt)
{
fprintf(stderr, "error creating connection point\n");
fflush(stderr);
return -1;
}
const char * conPtName = nzaeRemprotGetRemoteName();
if (!conPtName)
{
fprintf(stderr, "error getting connection point name\n");
fflush(stderr);
exit(-1);
}
if (nzaeconptSetName(hConpt, conPtName))
{
fprintf(stderr, "error setting connection point name\n");
fflush(stderr);
nzaeconptClose(hConpt);
return -1;
}
NzaeremprotInitialization args;
memset(&args, 0, sizeof(args));
args.ldkVersion = NZAE_LDK_VERSION;
args.hConpt = hConpt;
if (nzaeRemprotCreateListener(&args))
{
fprintf(stderr, "unable to create listener - %s\n", \
args.errorMessage);
fflush(stderr);
nzaeconptClose(hConpt);
return -1;
}
NZAEREMPROT_HANDLE hRemprot = args.handle;
NzaeApi api;
int i;
for (i = 0; i < 5; i++)
{
if (nzaeRemprotAcceptApi(hRemprot, &api))
{
fprintf(stderr, "unable to accept API - %s\n", \
nzaeRemprotGetLastErrorText(hRemprot));
fflush(stderr);
nzaeconptClose(hConpt);
nzaeRemprotClose(hRemprot);
return -1;
}
if (api.apiType != NZAE_API_FUNCTION)
{
fprintf(stderr, "unexpected API returned\n");
fflush(stderr);
nzaeconptClose(hConpt);
nzaeRemprotClose(hRemprot);
return -1;
}
printf("testcapi: accepted a remote request\n");
fflush(stdout);
run(api.handle.function);
}
nzaeRemprotClose(hRemprot);
nzaeconptClose(hConpt);
}
return 0;
}
static int run(NZAE_HANDLE h)
{
NzaeMetadata metadata;
if (nzaeGetMetadata(h, &metadata))
{
fprintf(stderr, "get metadata failed\n");
return -1;
}
#define CHECK(value) \
{ \
NzaeRcCode rc = value; \
if (rc) \
{ \
const char * format = "%s in %s at %d"; \
fprintf(stderr, format, \
nzaeGetLastErrorText(h), __FILE__, __LINE__); \
nzaeUserError(h, format, \
nzaeGetLastErrorText(h), __FILE__, __LINE__); \
exit(-1); \
} \
}
if (metadata.outputColumnCount != 1 ||
metadata.outputTypes[0] != NZUDSUDX_VARIABLE)
{
nzaeUserError(h, "expecting one output column of type string");
nzaeDone(h);
return -1;
}
if (metadata.inputColumnCount != 1)
{
nzaeUserError(h, "expecting one input column");
nzaeDone(h);
return -1;
}
if (metadata.inputTypes[0] != NZUDSUDX_FIXED
&& metadata.inputTypes[0] != NZUDSUDX_VARIABLE)
{
nzaeUserError(h, "first input column expected to be a string type");
nzaeDone(h);
return -1;
}
for (;;)
{
int i;
double result = 0;
NzaeRcCode rc = nzaeGetNext(h);
if (rc == NZAE_RC_END)
{
break;
}
NzudsData * input = NULL;
CHECK(nzaeGetInputColumn(h, 0, &input));
const char * opString;
if (input->isNull)
{
nzaeUserError(h, "first input column may not be null");
nzaeDone(h);
return -1;
}
if (input->type == NZUDSUDX_FIXED)
{
opString = input->data.pFixedString;
} else if (input->type == NZUDSUDX_VARIABLE)
{
opString = input->data.pVariableString;
} else
{
nzaeUserError(h, "first input column expected to be a string \
type");
nzaeDone(h);
return -1;
}
const char *ptr = opString;
char *token;
while ((token = strtok(ptr, ",")) != NULL) {
ptr = NULL;
CHECK(nzaeSetOutputString(h, 0, token));
CHECK(nzaeOutputResult(h));
}
}
nzaeDone(h);
return 0;
}

Utilice la compilación estándar:

$NZ_EXPORT_DIR/ae/utilities/bin/compile_ae --language system --version 3 \
--template compile sstring.c --exe sstring

Registra el ejecutable ' "sstring" ' recién creado:

$NZ_EXPORT_DIR/ae/utilities/bin/register_ae --language system --version 3 \
--template udtf --exe sstring --sig "sstring_c(VARCHAR(ANY))" \
--return "TABLE (val varchar(2000))"

Ejecute la consulta en nzsql:

SELECT * FROM TABLE WITH FINAL(sstring_c('12:30:15'));
VAL
----------
12:30:15
(1 row)
SELECT * FROM TABLE WITH FINAL(sstring_c('12:30:15,two,three'));
VAL
----------
12:30:15
two
three
(3 rows)
SELECT * FROM TABLE WITH FINAL(sstring_c(NULL));
ERROR: first input COLUMN may NOT be NULL