Re: - pgaql binary data date time fornats

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От Neeraj Rai
Тема Re: - pgaql binary data date time fornats
Дата
Msg-id 1369241530.69063.YahooMailAndroidMobile@web164901.mail.bf1.yahoo.com
обсуждение исходный текст
Ответ на ...  (Neeraj Rai <rneeraj@yahoo.com>)
Ответы - pgaql long value corrupted using htons
Список pgsql-interfaces
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Hi,

I forgot to mention that I'm trying to use binary data format.
I found exanples of sending string fornatted date time. However, i am assuming there are functions to covert unix time to pgtimestamptz and may be faster
Looking for inverse of ts.epoch

I can bypass bitwise fueld issue by assigning to int.
I think Q5 can be ignored. It should work the same for execparams and execprepared.

Thanks
Neeraj


From: Neeraj Rai <rneeraj@yahoo.com>;
To: pgsql-interfaces@postgresql.org <pgsql-interfaces@postgresql.org>;
Subject: [INTERFACES]
Sent: Wed, May 22, 2013 1:26:08 AM

Hi,
I'm trying a simple pgsql program with PQexecPrepared and have a few questions. 
I have seen the example but didn't find the answer there. googled too.

Q1. what format is date set in ? what is the length ?
Q2.Q2.what is the type and length of bit wise fields
Q3. how to convert seconds since epoch to date
Q4. is int passable as time?
Q5. the paramValsVec_ is char* const char[] . Can we type cast int to char* and pass in ? and set type to INT4OID?

Below is some pseudo code to put above questions in perspective.
>>. table 
CREATE TABLE t1
(curdate                 date,
str1                     varchar(19),
tm_new                  timestamptz,
count                       int);
>>> c++ code
 PGconn* pgconn; // connected
char * UpsertStmt_= "INSERT INTO t1 values( $1, $2, $3, $4)";
 int result=0;
 PGresult* pgres = PQprepare (pgconn, "stmtname", UpsertStmt_, 4, NULL);
  int result = PQresultStatus(pgres);
  PQclear(pgres_);

struct mydata
{
int curtime;
char str1[32];
int mycount;
 int mybitfield  : 3;
},
mydata myvar;
myvar.curtime = time(NULL)
strcpy(myvar.str1, hello);
myvar.mycount = 2;
myvar.mybitfield = 2;

  // set helper vars
 paramLenVec_[0]  = 8; // Q1. what format is date set in ? what is the length
 paramLenVec_[1]  = strlen(str1);
 paramLenVec_[2]  = sizeof(int);  // type = INT4OID, sizeof (int)
 paramLenVec_[3]  = sizeof(int); // Q2.what is the type and length of bit wise fields


  paramValsVec_[0]  = (char*)&myvar.curtime; // Q3. how to convert to date
  paramValsVec_[1]  = myvar.str1;
  paramValsVec_[2]  = &myvar.curtime; // Q4. is int passable as time
  paramValsVec_[3]  = (char*)&myvar.mycount; // Q5. 
PQexecPrepared (pgconn, "stmtname", 4, 
   paramValsVec_,
   paramLenVec_,
  NULL, 0
);


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