/* * testlibpq5.cc * Test the C++ version of LIBPQ, the POSTGRES frontend library. * tests the binary cursor interface * * * populate a database by doing the following (use testlibpq5.sql): CREATE TABLE test1 (i int4, d float4, p polygon); INSERT INTO test1 values (1, 3.567, '(3.0, 4.0, 1.0, 2.0)'::polygon); INSERT INTO test1 values (2, 89.05, '(4.0, 3.0, 2.0, 1.0)'::polygon); the expected output is: tuple 0: got i = (4 bytes) 1, d = (4 bytes) 3.567000, p = (4 bytes) 2 points boundbox = (hi=3.000000/4.000000, lo = 1.000000,2.000000) tuple 1: got i = (4 bytes) 2, d = (4 bytes) 89.050003, p = (4 bytes) 2 points boundbox = (hi=4.000000/3.000000, lo = 2.000000,1.000000) * */ #include #include "libpq++.h" #include extern "C" { #include "postgres.h" // for Postgres types #include "utils/geo_decls.h" // for the POLYGON type } main() { // Begin, by connecting to the backend using hardwired constants // and a test database created by the user prior to the invokation // of this test program. Connect using cursor interface. char* dbName = "dbname=template1"; // change this to the name of your test database PgCursor data(dbName, "mycursor"); // check to see that the backend connection was successfully made if ( data.ConnectionBad() ) { cerr << "Connection to database '" << dbName << "' failed." << endl << data.ErrorMessage(); exit(1); } // Declare a binary cursor for all the tuples in database 'test1' if ( !data.Declare("select * from test1", 1) ) { cerr << "DECLARE CURSOR command failed" << endl; exit(1); } // fetch all instances from the current cursor if ( !data.Fetch() ) { cerr << "FETCH ALL command didn't return tuples properly" << endl; exit(1); } // Find the field numbers for the columns 'i', 'd', and 'p' int i_fnum = data.FieldNum("i"); int d_fnum = data.FieldNum("d"); int p_fnum = data.FieldNum("p"); /* for (i=0;i<3;i++) { printf("type[%d] = %d, size[%d] = %d\n", i, data.FieldType(i), i, data.FieldSize(i)); } */ // Print out the information about the extracted tuple for (int i=0; i < data.Tuples(); i++) { // we hard-wire this to the 3 fields we know about int* ival = (int*)data.GetValue(i,i_fnum); float* dval = (float*)data.GetValue(i,d_fnum); int plen = data.GetLength(i,p_fnum); // Allocate correct memory space for the Polygon struct and copy // the extracted data into it. // plen doesn't include the length field so need to increment by VARHDSZ POLYGON* pval = (POLYGON*) malloc(plen + VARHDRSZ); pval->size = plen; memmove((char*)&pval->npts, data.GetValue(i,p_fnum), plen); // Display Polygon Information cout << "tuple " << i << ": got" << endl << " i = (" << data.GetLength(i,i_fnum) << " bytes) " << *ival << "," << endl << " d = (" << data.GetLength(i,d_fnum) << " bytes) " << *dval << "," << endl << " p = (" << data.GetLength(i,d_fnum) << " bytes) " << pval->npts << " points" << "\tboundbox = (hi=" << pval->boundbox.high.x << "/" << pval->boundbox.high.y << "," << "lo = " << pval->boundbox.low.x << "," << pval->boundbox.low.y << ")" << endl; // Deallocate memory allocated for the Polygon structure free(pval); } return 0; }