The following example implements ordering functionality that allows Vantage to order two circle_t UDTs by their area. The function gets the radius and computes the area, returning the result as a FLOAT data type. If the circle is null or if the x attribute, y attribute, or radius attribute of the circle is null, the function returns a null result.
/* File: c_order.c */ #define SQL_TEXT Latin_Text #include <sqltypes_td.h> #include <string.h> void circle_t_Ordering( UDT_HANDLE *circleUdt, FLOAT *result, int *indicator_circle, int *indicator_result, char sqlstate[6], SQL_TEXT extname[129], SQL_TEXT specific_name[129], SQL_TEXT error_message[257]) { INTEGER x, y, r; int nullIndicator; int length; /* If circle is null, return null. */ if (*indicator_circle == -1) { *indicator_result = -1; return; } /* Verify that the x attribute is not null. */ FNC_GetStructuredAttribute(*circleUdt, "x", &x, SIZEOF_INTEGER, &nullIndicator, &length); if (nullIndicator == -1) { *indicator_result = -1; return; } /* Verify that the y attribute is not null. */ FNC_GetStructuredAttribute(*circleUdt, "y", &y, SIZEOF_INTEGER, &nullIndicator, &length); if (nullIndicator == -1) { *indicator_result = -1; return; } /* Get the radius attribute. */ FNC_GetStructuredAttribute(*circleUdt, "radius", &r, SIZEOF_INTEGER, &nullIndicator, &length); if (nullIndicator == -1) { *indicator_result = -1; return; } *result = 3.14 * r * r; }
The following example implements transform functionality that transforms a VARCHAR(80) from the client to a circle_t type on the server. The character string contains x, y, radius and color attributes separated by a colon ( : ) delimiter:
x:y:r:color
The absence of a value indicates a null attribute. For example, the format for a null radius is:
x:y::color
/* File: c_tosql.c */ #define SQL_TEXT Latin_Text #include <sqltypes_td.h> #include <string.h> void circle_t_ToSql( VARCHAR_LATIN *p1, UDT_HANDLE *resultCircleUdt, char sqlstate[6]) { char buf[81]; char *x_str, *y_str, *r_str, *color; char *p; INTEGER x, y, r; int nullIndicator; int len; /* Make a copy of the input string since we want to modify it. */ strcpy(buf, (char *)p1); /* Retrieve and set the x coordinate field */ x_str = buf; p = strchr(x_str, ':'); *p = '\0'; if (x_str[0] == '\0') { nullIndicator = -1; } else { nullIndicator = 0; x = atoi(x_str); } p++; FNC_SetStructuredAttribute(*resultCircleUdt, "x", &x, nullIndicator, SIZEOF_INTEGER); /* Retrieve and set the y coordinate field */ y_str = p; p = strchr(y_str, ':'); *p = '\0'; if (y_str[0] == '\0') { nullIndicator = -1; } else { nullIndicator = 0; y = atoi(y_str); } p++; FNC_SetStructuredAttribute(*resultCircleUdt, "y", &y, nullIndicator, SIZEOF_INTEGER); /* Retrieve and set the radius field */ r_str = p; p = strchr(r_str, ':'); *p = '\0'; if (r_str[0] == '\0') { nullIndicator = -1; } else { nullIndicator = 0; r = atoi(r_str); } p++; FNC_SetStructuredAttribute(*resultCircleUdt, "radius", &r, nullIndicator, SIZEOF_INTEGER); /* Retrieve and set the color field */ color = p; if (color[0] == '\0') { nullIndicator = -1; } else { nullIndicator = 0; } len = strlen(color); FNC_SetStructuredAttribute(*resultCircleUdt, "color", (VARCHAR_LATIN *)color, nullIndicator, SIZEOF_VARCHAR_LATIN(len)); }
The following example implements transform functionality that allows Vantage to export a circle_t type as a VARCHAR(80):
/* File: c_fromsql.c */ #define SQL_TEXT Latin_Text #include <sqltypes_td.h> #include <string.h> void circle_t_FromSql( UDT_HANDLE *circleUdt, VARCHAR_LATIN *result, char sqlstate[6]) { INTEGER x, y, r; char y_str[11], r_str[11]; VARCHAR_LATIN color[81]; int nullIndicator; int length; /* Get each of the attributes and write them to the result string. */ FNC_GetStructuredAttribute(*circleUdt, "x", &x, SIZEOF_INTEGER, &nullIndicator, &length); if (nullIndicator == 0) sprintf((char *)result, "%d:", x); else strcpy((char *)result, ":"); FNC_GetStructuredAttribute(*circleUdt, "y", &y, SIZEOF_INTEGER, &nullIndicator, &length); if (nullIndicator == 0) { sprintf(y_str, "%d", y); strcat((char *)result, y_str); } strcat((char *)result, ":"); FNC_GetStructuredAttribute(*circleUdt, "radius", &r, SIZEOF_INTEGER, &nullIndicator, &length); if (nullIndicator == 0) { sprintf(r_str, "%d", r); strcat((char *)result, r_str); } strcat((char *)result, ":"); FNC_GetStructuredAttribute(*circleUdt, "color", color, SIZEOF_VARCHAR_LATIN_WITH_NULL(80), &nullIndicator, &length); if (nullIndicator == 0) strcat((char *)result, (char *)color); }