how to read database into dataset

KPI_LOOKUP, the columnheader is not fixed length, that is to say ,the data in table is possible such as "1,country;month;amcount" and there is also another possible "1,country;month;quarter;quantity;amount" and so on .
and kpi_lookup_detail,the content data is also like this.

public DataSet constructionDataSet(int kpi_lookup_id)
{
    DataSet customDs = new DataSet("kpi_lookup");
    DataTable customDt = customDs.Tables.Add("kpi");

    string strColumnHeader = this.getColumnHeader(kpi_lookup_id);
    string[] strListArray = this.getArrayViaString(strColumnHeader);
    int ii = 0;
    foreach (string m in strListArray)
    {
        customDt.Columns.Add(m, typeof(string));
        ii = ii + 1;
    }
    DataSet ds = this.GetKPIContent(kpi_lookup_id);
    foreach (DataRow dr in ds.Tables[0].Rows)  //Tables[0] actually is the customDt
    {
        string[] contentArray = dr.ItemArray[0].ToString().Split(';');
        DataRow newCustomersRow = customDs.Tables["kpi"].NewRow();
        for (int j = 0; j < contentArray.Length; j++)
        {
            newCustomersRow[j] = contentArray[j];
        }
   
        customDt.Rows.Add(newCustomersRow);
    }

    return customDs;
}

public string getColumnHeader(int kpi_lookup_id)
{
    string strSql = @"select 'ID'||columnheader  AS columnheader 
                         from kpi_lookup where id = " + kpi_lookup_id;
    string strColumnHeader;
    OracleConnection conn = this.DBCon();
    conn.Open();
    OracleDataAdapter oda = new OracleDataAdapter(strSql, conn);
    DataSet ds = new DataSet();
    oda.Fill(ds);
    strColumnHeader = ds.Tables[0].Rows[0][0].ToString();
    ds.Dispose();
    return strColumnHeader;
}

public string[] getArrayViaString(string columnHeader)
{
    string[] strArrayColumnHeaderList = columnHeader.Split(';');
    return strArrayColumnHeaderList;
}

public DataSet GetKPIContent(string sqlText)
{
    OracleConnection conn = DBCon();
    conn.Open();
    OracleDataAdapter oda = new OracleDataAdapter(sqlText, conn);
    DataSet ds = new DataSet();
    oda.Fill(ds);
    conn.Close();
    return ds;
}

public DataSet GetKPIContent(int kpi_lookup_id)
{
    string strSql = "select id||content as content from
                       kpi_lookup_detail where kpi_lookup_id ="+kpi_lookup_id +" order by id";
    DataSet ds = this.GetKPIContent(strSql);
    return ds;
}