如何在使用Oracle OCCI库迭代结果时计算列的数量

Question

帮助我，我想做一个通用的函数，得到任何查询字符串的结果，并把所有行到另一个变量。当迭代一行时，我如何知道可用的列数?

Environment *env = Environment::createEnvironment();
Connection *conn = env->createConnection("user","pass");
quantLinhas = 0;
if( conn != NULL ) {
    Statement *stmt = conn->createStatement(query);
    ResultSet *rs = stmt->executeQuery();
    resultadoSQL->linhas.clear();
    while (rs->next()) {
        aux.campos.clear();
        numbers_colums = rs->whatever_method() //WHAT DO I DO HERE??
        for(i = 0; i < numbers_colums ; i++) {  
            aux.campos.push_back( rs->getString(i) );
            quantLinhas++;
        }
        resultadoSQL->linhas.push_back( aux );
    }
    stmt->closeResultSet(rs);
    conn->terminateStatement(stmt);
    env->terminateConnection(conn);
}

Answer 1

根据文档，您可以使用getColumnListMetaData函数。返回向量中的元素个数可能是您想要的。您可以检查每个元素是否为PTYPE_COL以确保它。

Answer 2

try this

  vector<MetaData> columnList = rs->getColumnListMetaData();
  numbers_colums = columnList.size();
  columnList.clear();

它对我有效。源链接