Postgres95 1.01 Distribution - Virgin Sources

src/interfaces/libpq++/examples/testlibpq1.cc

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+/*
+ * testlibpq.cc
+ * 	Test the C++ version of LIBPQ, the POSTGRES frontend library.
+ *
+ *  queries the template1 database for a list of database names 
+ *
+ */
+#include <stdio.h>
+#include "libpq++.H"
+
+main()
+{
+  char* dbName;
+  int nFields;
+  int i,j;
+
+  /* begin, by creating the parameter environtment for a backend
+     connection. When no parameters are given then the system will
+     try to use reasonable defaults by looking up environment variables 
+     or, failing that, using hardwired constants */
+  PGenv env;
+  PGdatabase* data;
+
+  /* Select a database */
+  dbName = "template1";
+
+  /* make a connection to the database */
+  data = new PGdatabase(&env, dbName);
+
+  /* check to see that the backend connection was successfully made */
+  if (data->status() == CONNECTION_BAD) {
+    fprintf(stderr,"Connection to database '%s' failed.\n", dbName);
+    fprintf(stderr,"%s",data->errormessage());
+    delete data;
+    exit(1);
+  }
+
+  /* start a transaction block */
+  if(data->exec("BEGIN") != PGRES_COMMAND_OK) {
+    fprintf(stderr,"BEGIN command failed\n");
+    delete data;
+    exit(1);
+  }
+
+  /* fetch instances from the pg_database, the system catalog of databases*/
+  if (data->exec("DECLARE myportal CURSOR FOR select * from pg_database")
+      != PGRES_COMMAND_OK) {
+    fprintf(stderr,"DECLARE CURSOR command failed\n");
+    delete data;
+    exit(1);
+  }
+
+  if(data->exec("FETCH ALL in myportal") != PGRES_TUPLES_OK) {
+    fprintf(stderr,"FETCH ALL command didn't return tuples properly\n");
+    delete data;
+    exit(1);
+  }
+ 
+  /* first, print out the attribute names */
+  nFields = data->nfields();
+  for (i=0; i < nFields; i++) {
+    printf("%-15s",data->fieldname(i));
+  }
+  printf("\n\n");
+
+  /* next, print out the instances */
+  for (i=0; i < data->ntuples(); i++) {
+    for (j=0  ; j < nFields; j++) {
+      printf("%-15s", data->getvalue(i,j));
+    }
+    printf("\n");
+  }
+
+  /* close the portal */
+  data->exec("CLOSE myportal");
+
+  /* end the transaction */
+  data->exec("END");
+
+  /* close the connection to the database and cleanup */
+  delete data;
+}
+  
+