[NOVICE]Convert Datum to an user-defined data type?
Hi everyone,
I have created a new data types using SQL in a database:
CREATE TYPE *type1* AS (
score integer,
time integer[],
);
I also created a server extension module (C code), and I was able to
retrieve a Datum value of *type1 *from the database (using SPI_ functions)
My question is: how can I convert that Datum value back to type1 data
structure (in C code), so I can easily deal with score and time values?
typedef struct *type1*{
int score;
int *time;
} type1;
PS: I really don't want to deal with cstring to in order to get the score
and time attributes.
Many thanks :)
On Mon, Mar 10, 2014 at 11:09 PM, Anh Pham <atpham.wpi@gmail.com> wrote:
Hi everyone,
I have created a new data types using SQL in a database:CREATE TYPE type1 AS (
score integer,
time integer[],
);I also created a server extension module (C code), and I was able to
retrieve a Datum value of type1 from the database (using SPI_ functions)
My question is: how can I convert that Datum value back to type1 data
structure (in C code), so I can easily deal with score and time values?
I wonder if you read section 35.9.8 about using "funcapi.h" here:
http://www.postgresql.org/docs/9.1/static/xfunc-c.html
I suggest you read more about the following functions and how they are
to be used (quoting brief descriptions from the page here):
* To get a TupleDesc based on a type OID, call:
TupleDesc TypeGetTupleDesc(Oid typeoid, List *colaliases)
* Once you have a TupleDesc, call:
TupleDesc BlessTupleDesc(TupleDesc tupdesc)
* With the blessed tupdesc, given user data in Datum form, to build a
HeapTuple, use:
HeapTuple heap_form_tuple(TupleDesc tupdesc, Datum *values, bool *isnull)
--
Amit
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