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103 lines
3.3 KiB
C++
103 lines
3.3 KiB
C++
/*
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* testlibpq5.cc
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* Test the C++ version of LIBPQ, the POSTGRES frontend library.
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* tests the binary cursor interface
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*
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*
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*
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populate a database by doing the following (use testlibpq5.sql):
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CREATE TABLE test1 (i int4, d float4, p polygon);
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INSERT INTO test1 values (1, 3.567, '(3.0, 4.0, 1.0, 2.0)'::polygon);
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INSERT INTO test1 values (2, 89.05, '(4.0, 3.0, 2.0, 1.0)'::polygon);
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the expected output is:
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tuple 0: got
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i = (4 bytes) 1,
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d = (4 bytes) 3.567000,
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p = (4 bytes) 2 points boundbox = (hi=3.000000/4.000000, lo = 1.000000,2.000000)
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tuple 1: got
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i = (4 bytes) 2,
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d = (4 bytes) 89.050003,
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p = (4 bytes) 2 points boundbox = (hi=4.000000/3.000000, lo = 2.000000,1.000000)
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*
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*/
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#include <iostream.h>
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#include <libpq++.h>
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#include <stdlib.h>
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extern "C" {
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#include "postgres.h" // for Postgres types
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#include "utils/geo_decls.h" // for the POLYGON type
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}
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main()
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{
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// Begin, by connecting to the backend using hardwired constants
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// and a test database created by the user prior to the invokation
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// of this test program. Connect using cursor interface.
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char* dbName = getenv("USER"); // change this to the name of your test database
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PgCursor data(dbName, "mycursor");
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// check to see that the backend connection was successfully made
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if ( data.ConnectionBad() ) {
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cerr << "Connection to database '" << dbName << "' failed." << endl
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<< data.ErrorMessage();
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exit(1);
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}
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// Declare a binary cursor for all the tuples in database 'test1'
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if ( !data.Declare("select * from test1", 1) ) {
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cerr << "DECLARE CURSOR command failed" << endl;
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exit(1);
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}
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// fetch all instances from the current cursor
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if ( !data.Fetch() ) {
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cerr << "FETCH ALL command didn't return tuples properly" << endl;
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exit(1);
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}
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// Find the field numbers for the columns 'i', 'd', and 'p'
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int i_fnum = data.FieldNum("i");
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int d_fnum = data.FieldNum("d");
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int p_fnum = data.FieldNum("p");
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/*
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for (i=0;i<3;i++) {
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printf("type[%d] = %d, size[%d] = %d\n",
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i, data.FieldType(i),
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i, data.FieldSize(i));
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}
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*/
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// Print out the information about the extracted tuple
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for (int i=0; i < data.Tuples(); i++) {
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// we hard-wire this to the 3 fields we know about
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int* ival = (int*)data.GetValue(i,i_fnum);
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float* dval = (float*)data.GetValue(i,d_fnum);
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int plen = data.GetLength(i,p_fnum);
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// Allocate correct memory space for the Polygon struct and copy
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// the extracted data into it.
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// plen doesn't include the length field so need to increment by VARHDSZ
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POLYGON* pval = (POLYGON*) malloc(plen + VARHDRSZ);
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pval->size = plen;
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memmove((char*)&pval->npts, data.GetValue(i,p_fnum), plen);
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// Display Polygon Information
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cout << "tuple " << i << ": got" << endl
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<< " i = (" << data.GetLength(i,i_fnum) << " bytes) " << *ival << "," << endl
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<< " d = (" << data.GetLength(i,d_fnum) << " bytes) " << *dval << "," << endl
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<< " p = (" << data.GetLength(i,d_fnum) << " bytes) " << pval->npts << " points"
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<< "\tboundbox = (hi=" << pval->boundbox.high.x << "/" << pval->boundbox.high.y << ","
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<< "lo = " << pval->boundbox.low.x << "," << pval->boundbox.low.y << ")" << endl;
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// Deallocate memory allocated for the Polygon structure
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free(pval);
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}
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}
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