// Selects a record with an SQL statement.
private static Person RetrieveClientSql(DbDataAccess dbDataAccess
    , DbColumns dataDefinition)
{
    Person retValue = null;

    StringBuilder builder = new StringBuilder(64);
    builder.AppendLine("select * from PersonTest");
    builder.AppendLine("where Name = 'TestName'");
    string sql = builder.ToString();

    DbColumns dataColumns = null;
    bool isColumnModifications = true;
    if (isColumnModifications)
    {
        // Create the list of included columns.
        // This list should include the database assigned columns.
        List<string> columnNames = new List<string>();
        foreach (DbColumn column in dataDefinition)
        {
            columnNames.Add(column.ColumnName);
        }

        // Create a Data Columns object with the included data definitions
        // and values from the data record.
        dataColumns = DbCommon.QueryColumns(columnNames, dataDefinition);
    }
    
    DbRequest dbRequest = new DbRequest()
    {
        ClientSql = sql
        Columns = dataColumns,
        QueryType = QueryType.RetrieveSQL.ToString(),
        TableName = "PersonTest",
    };
    DbResult dbResult = dbDataAccess.Execute(dbRequest);
    
    if (dbResult != null)
    {
        string sqlStatement = dbResult.ExecutedSql;
        if (dbResult.DbRecords != null && dbResult.DbRecords.Count > 0)
        {
            retValue = new Person();
            DbCommon.SetObjectValues(dbResult.DbRecords[0], retValue);
        }
    }
    return retValue;
}