Set the value of a Geometry type using a Well-Known Text (WKT) string representation of the Geometry in the Latin character set.
Syntax
void FNC_GeomGetWKT(GEO_HANDLE geoHandle, unsigned char* wkt, FNC_GeomSize_t wktSize, int srid)
Syntax Elements
- geoHandle
- A handle to a Geometry type that is defined to be a return value for a UDF/UDM or an INOUT/OUT parameter to an external stored procedure.
- wkt
- A pointer to the WKT string in the Latin character set.
- wktSize
- Size in bytes of the WKT string.
- srid
- Spatial Reference System Identifier of the Geometry to be set.
Usage Notes
The FNC_GeomSetWKT function sets the value of a Geometry using a WKT string representation. The wkt parameter containing the WKT string, the wktSize, and the SRID to be set for the Geometry are passed as input.
The FNC_GeomSetWKT function should be called only for inline ST_Geometry values. If used with a LOB-based ST_Geometry value, a 7579 error is generated: FNC_GeomSetWKT is only valid for inline ST_Geometry values.
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);
}
}