Purpose
Returns information about the ST_Geometry value including its size and whether it stores its value as a LOB.
Syntax
void FNC_GetGeometryInfo(GEO_HANDLE geoHandle, FNC_GeomSize_t *maxLength, int *numLobs)
- GEO_HANDLE geoHandle
- A handle to an ST_Geometry type that is defined to be an input or output parameter to an external routine.
- FNC_GeomSize_t *maxLength
- The maximum length possible for this ST_Geometry value.
- int *numLobs
- If this ST_Geometry object stores its value as a LOB, numLobs is 1, otherwise numLobs is 0.
Usage Notes
FNC_GetGeomInfo returns information about the ST_Geometry value such as its maximum size and whether it uses a LOB to store its value. The GEO_HANDLE for the ST_Geometry value is passed in as input, and the maximum size and whether it can store its value as a LOB is returned to the caller.
Example: Using FNC_GeomGetWKT to retrieve a ST_Geometry WKT
The following example function takes a ST_Geometry parameter and retrieves the Well Known Text format for the geometry. It returns the string back in the ST_Geometry return parameter.
CREATE FUNCTION geomUDF1(P1 st_geometry(1000))
RETURNS ST_GEOMETRY(1000)
NO SQL
PARAMETER STYLE SQL
DETERMINISTIC
LANGUAGE C
EXTERNAL NAME 'CS!geomUDF1!geomUDF1.c';
void geomUDF1(GEO_HANDLE* geom_handle,
GEO_HANDLE* return_handle,
int* indicator_thisGeom,
int* indicator_returnGeom,
char sqlstate[6],
SQL_TEXT extname[129],
SQL_TEXT specific_name[129],
SQL_TEXT error_message[257] )
{
FNC_GeomSize_t geomsize;
FNC_GeomSize_t wktSize;
char* wktBuffer;
FNC_GeomSize_t wktBufferSize;
int srid , max_length, numLobs;
/* Get the Geometry Info */
FNC_GetGeometryInfo(*geom_handle,&max_length, &numLobs);
if(numLobs == 0)
{
/* Get the Geometry WKT Size */
geomsize = FNC_GeomGetWKTSize(*geom_handle);
/* Allocate the buffer to hold the WKT. Note that we add
1 for the null termination character. */
wktBuffer = (char*)FNC_Malloc(geomsize + 1);
wktBufferSize = geomsize + 1;
/* Get the WKT string */
FNC_GeomGetWKT(*geom_handle,wktBuffer, wktBufferSize,
&wktSize, &srid);
/* Set the WKT string as return value */
FNC_GeomSetWKT(*return_handle, wktBuffer, wktSize,0);
*indicator_returnGeom = 0;
FNC_free(wkbBuffer);
}
}