[postgis-devel] Geometry Uses

[Leticia]

Hi, I need to build a new index. It is similar to R-tree but their entries
nodes contains not only the MBRs but some numeric information.

I am using a "CREATE TYPE" in order to create the data type for the table.
The SQL sentences look like

 

.

 

CREATE TYPE New_Type

(

   internallength = -1, 

   input = New_Type_IN,

   output = New_Type_OUT,

   storage= plain

);

 

.

 

CREATE TABLE proof (col   New_type);

 

CREATE INDEX anIndex ON proof USING GiST(  col   New_Type_Ops);

.

 

 

As I am creating an opaque data type, I need to create an equivalent one in
C language. I need something like this:

 

/* C language */

typedef struct My_New_Type

{

    unsigned int               size;
/* required to be a Postgres varlena type */

    float                          number;            

    PG_LWGEOM           geometry;                     

} My_New_Type;

 

As I need to store a "geometry" inside the opaque data type, I use "varlena
type" convention for my declaration. The variable length (size) is because
the geometry that I have to store. I only have to store one geometry inside
my structure.

 

Must I use PG_LWGEOM?  Must I use LWGEOM?

Is it OK to declare my struct as VARIABLE because I encapsulate a GEOMETRY?

 

 

Could you help me?

Thanks in advance,

Leticia

 

 

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