Query method example

The queryex.cpp example demonstrates use of the ExecForStatus, ExecOneRow, and ExecToSet methods.

The following excerpts illustrate the use of the query methods in the queryex.cpp example:
  1. Call ITQuery::ExecOneRow() to check if the table informixfans exists in the database. If the table does not exist, use ITQuery::ExecForStatus() to create it. 
    // Does the table exist? If not, then create it.
ITRow *r1 = q.ExecOneRow(
    "select owner from systables where tabname = 'informixfans';");
if (!r1
     && (!q.ExecForStatus(
         "create table informixfans (name varchar(128));")))
    {
    cerr << "Could not create table 'informixfans'!" << endl;
    return 1;
    }
  2. Call ITQuery::ExecToSet to fetch the results of a select statement: 
    // Show the contents of the table
cout << "These are the members of the Informix fan club, version ";
ITValue *rel = q.ExecOneRow 
    ("select owner from systables where tabname = ' VERSION';");
cout << rel->Printable() << " ALWAYS_DIFFERENT" << endl;
rel->Release(); 

ITSet *set = q.ExecToSet
    ("select * from informixfans order by 1;"); 
if(!set)
{
    cout << "Query failed!" << endl;
    conn.SetTransaction(ITConnection::Abort);
    conn.Close();
    return -1;
}
ITValue *v;
while ((v = set->Fetch()) != NULL)
{
    cout << v->Printable() << endl;
    v->Release();
} 
set->Release();